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Comprehensive genomic profiling (CGP) has been approved in Japan since June 2019, enabling mutation-specific therapy. Although tissue sampling via endoscopic ultrasound-guided tissue acquisition (EUS-TA) is standard in pancreatic cancer, reports on obtaining appropriate samples for CGP, especially for the OncoGuide NCC Oncopanel System (NOP) and FoundationOne CDx (FOne), are lacking. Therefore, we investigated the success rate and factors related to appropriate EUS-TA sampling for CGP analysis suitability in unresectable pancreatic ductal adenocarcinoma (UR-PDAC).Participants comprised 150 UR-PDAC patients who underwent EUS-TA and tumor sample evaluation for CGP analysis suitability between June 2019 and December 2021. The proportion of patients meeting the criteria was evaluated considering tumor size, puncture lesion, presence of metastasis, type and size of puncture needle, suction method, number of punctures, and puncture route.In total, 39.2% (60/153) of samples met NOP analysis suitability criteria and 0% met FOne analysis suitability criteria. The suitability rate was significantly higher with 19G fine-needle biopsy (FNB) (56.0%; 42/75) than with 22G FNB (32.6%; 14/43) and 22G fine-needle aspiration (11.4%; 4/35). Nineteen-gauge needle (odds ratio [OR] 2.53; 95% confidence interval [CI] 1.15-5.57; P = 0.021) and FNB (OR 3.57; 95% CI 1.05-12.20; P = 0.041) were independent factors contributing to NOP analysis suitability. Among 30 patients who underwent actual NOP analysis, the analysis success rate was 100% (30/30).In sample collection via EUS-TA, 19G and FNB needles contribute to NOP analysis suitability.

In a patient with a history of cancer, distinguishing a metastasis of the prior tumour from a new primary tumour relies on the comparison of morphological features between the tumour of concern and the prior tumour, often with the aid of immunohistochemistry. This approach is the basis of pathological diagnosis, but recent advances in precision cancer medicine and cancer treatments change the situation. We here present a case report of lung cancer, mimicking primary lung adenocarcinoma, with minute foci of metastatic thyroid papillary carcinoma, in a 34-year-old man with a history of papillary thyroid carcinoma. Through the analysis of thyroid tumor and lung tumor at the age of 4 and 34 years in this patient, identical NCOA4-RET translation suggested histological conversion, which was induced probably due to high selective pressure by the treatment. As histological transformation of non-small cell lung cancer is well documented as a form of recurrence after EGFR-tyrosine kinase inhibitor treatment, the lineage conversion in association with effective treatments may be a diagnostic pitfall in the era of precision cancer medicine.

Heterogeneous nuclear ribonucleoprotein L‐like (HNRNPLL), a suppressor of colorectal cancer (CRC) metastasis, is transcriptionally downregulated when CRC cells undergo epithelial‐mesenchymal transition (EMT). Here we show that decrease of MYB mediates the downregulation of HNRNPLL during EMT. The promoter activity was attributed to a region from −273 to −10 base pairs upstream of the transcription start site identified by 5'‐RACE analysis, and the region contained potential binding sites for MYB and SP1. Luciferase reporter gene assays and knockdown or knockout experiments for genes encoding the MYB family proteins, MYB, MYBL1, and MYBL2, revealed that MYB was responsible for approximately half of the promoter activity. On the other hand, treatment with mithramycin A, an inhibitor for SP1 and SP3, suppressed the promoter activity and their additive contribution was confirmed by knockout experiments. The expression level of MYB was reduced on EMT while that of SP1 and SP3 was unchanged, suggesting that the downregulation of HNRNPLL during EMT was mediated by the decrease of MYB expression while SP1 and SP3 determine the basal transcription level of HNRNPLL. Histopathological analysis confirmed the accumulation of MYB‐downregulated cancer cells at the invasion front of clinical CRC tissues. These results provide an insight into the molecular mechanism underlying CRC progression., Heterogeneous nuclear ribonucleoprotein L‐like (HNRNPLL), a suppressor of colorectal cancer (CRC) metastasis, is transcriptionally downregulated when CRC cells undergo epithelial‐mesenchymal transition (EMT). Here we show that decrease of MYB mediates the downregulation of HNRNPLL during EMT.

Comprehensive genomic profiling (CGP) is being increasingly used for the routine clinical management of solid cancers. In July 2018, the use of tumor tissue‐based CGP assays became available for all solid cancers under the universal health insurance system in Japan. Several restrictions presently exist, such as patient eligibility and limitations on the opportunities to perform such assays. The clinical implementation of CGP based on plasma circulating tumor DNA (ctDNA) is also expected to raise issues regarding the selection and use of tissue DNA and ctDNA CGP. A Joint Task Force for the Promotion of Cancer Genome Medicine comprised of three Japanese cancer‐related societies has formulated a policy proposal for the appropriate use of plasma CGP (in Japanese), available at https://www.jca.gr.jp/researcher/topics/2021/files/20210120.pdf, http://www.jsco.or.jp/jpn/user_data/upload/File/20210120.pdf, and https://www.jsmo.or.jp/file/dl/newsj/2765.pdf. Based on these recommendations, the working group has summarized the respective advantages and cautions regarding the use of tissue DNA CGP and ctDNA CGP with reference to the advice of a multidisciplinary expert panel, the preferred use of plasma specimens over tissue, and multiple ctDNA testing. These recommendations have been prepared to maximize the benefits of performing CGP assays and might be applicable in other countries and regions.

BRAF mutations are rare driver mutations in non-small cell lung cancer (NSCLC), accounting for 1%-2% of the driver mutations, and the mutation spectrum has a wide range in contrast to other tumors. While V600E is a dominant mutation in melanoma, more than half of the mutations in NSCLCs are non-V600E. However, treatment with dabrafenib plus trametinib targets the BRAF V600E mutation exclusively. Therefore, distinguishing between V600E and non-V600E mutations is crucial for biomarker testing in NSCLC in order to determine treatment of choice. Immunohistochemistry (IHC) using the BRAF V600E mutation-specific antibody is clinically used in melanoma patients, but little is known about its application in NSCLC, particularly with regard to the assay performance for non-V600E mutations. In the present study, we examined 117 tumors with BRAF mutations, including 30 with non-V600E mutations, using BRAF mutation-specific IHC. None of the tumors with non-V600E mutations, including two compound mutations, showed a positive reaction. Furthermore, all V600E mutations were positive except for one case with combined BRAF V600E and K601_W604 deletion. Our findings confirmed that the BRAF V600E mutation-specific IHC is specific without any cross-reactions to non-V600E mutations, suggesting that this assay can be a useful screening tool in clinical practice.

Aims Anaplastic lymphoma kinase (ALK) immunohistochemistry has shifted from being a screening tool to being a sole determinant for ALK-targeted therapy. Recent articles have referred to small-cell lung cancer (SCLC) transformation as a resistance mechanism after ALK inhibitor treatments, but few reports have addressed ALK expression in treatment-naive SCLC in a comprehensive manner. Therefore, we examined ALK expression and the mechanisms in treatment-naive SCLCs. Methods and results We examined ALK expression in a consecutive series of SCLC tumours, and the expression mechanism was analysed regarding gene rearrangement, copy number changes, and point mutations. We also examined whether SCLC with ALK expression can be suppressed by crizotinib treatment in vitro. Immunohistochemical results revealed that ALK was expressed in 16 of 142 (11.3%) SCLCs. The expression was focal and less intense, which is in contrast to strong and uniform expression in adenocarcinoma with ALK rearrangement. Two combined SCLCs showed a positive reaction restricted to the SCLC component. None of the known genetic alterations, including rearrangement, amplification, copy number gain, or point mutations, were associated with ALK expression. A SCLC cell line, SKLC2, which expressed ALK without known genetic alterations, was not inhibited by a practically achievable serum concentration of crizotinib. Conclusions Anaplastic lymphoma kinase immunohistochemistry for treatment-naive SCLCs should not be used as a predictive biomarker for ALK inhibitor therapy, because the positive reactions were due to intrinsic expression of normal ALK transcript.

Spontaneous regression (SR) of cancer implies the partial or complete disappearance of malignant disease without or with adequate medical treatment. Typically, SR of cancer is a sporadic event, especially in non-small cell lung cancer (NSCLC). Although the underlying mechanism of SR remains unknown, stimulation of an immunological response has been proposed. Herein, we report the case of a 56-year-old woman exhibiting SR of NSCLC with a mediastinal disease. Despite regression of the primary site after a lung biopsy, simultaneous progression of mediastinal lymph node metastasis occurred. Specimens obtained by surgical resection pathologically confirmed both primary and metastatic sites. Reportedly, primary and metastatic tumors shrink synchronously in SR of metastatic NSCLCs. Thus, the fact that the SR of NSCLC can present inconsistent development in primary and metastatic sites should be considered, and direct intervention is recommended if physicians diagnose this phenomenon.

Heterogeneous nuclear ribonucleoprotein L-like (HNRNPLL), an RNA-binding protein that regulates alternative splicing of pre-mRNA, has been shown to regulate differentiation of lymphocytes, as well as metastasis of colorectal cancer cells. Here, we show that HNRNPLL promotes cell cycle progression and, hence, proliferation of colorectal cancer cells. Functional annotation analysis of those genes whose expression levels were changed threefold or more in RNA sequencing analysis between SW480 cells overexpressing HNRNPLL and those knocked down for HNRNPLL revealed enrichment of DNA replication-related genes by HNRNPLL overexpression. Among 13 genes detected in the DNA replication pathway, PCNA, RFC3 and FEN1 showed reproducible upregulation by HNRNPLL overexpression both at mRNA and at protein levels in SW480 and HT29 cells. Importantly, knockdown of any of these genes alone suppressed the proliferation-promoting effect induced by HNRNPLL overexpression. RNA-immunoprecipitation assay presented a binding of FLAG-tagged HNRNPLL to mRNA of these genes, and HNRNPLL overexpression significantly suppressed the downregulation of these genes during 12 h of actinomycin D treatment, suggesting a role of HNRNPLL in mRNA stability. Finally, analysis of a public RNA sequencing dataset of clinical samples suggested a link between overexpression of HNRNPLL and that of PCNA, RFC3 and FEN1. This link was further supported by immunohistochemistry of colorectal cancer clinical samples, whereas expression of CDKN1A, which is known to inhibit the cooperative function of PCNA, RFC3 and FEN1, was negatively associated with HNRNPLL expression. These results indicate that HNRNPLL stabilizes mRNA encoding regulators of DNA replication and promotes colorectal cancer cell proliferation.

The anaplastic variant of diffuse large B-cell lymphoma (A-DLBCL) is morphologically defined but remains an enigmatic disease in its clinicopathologic distinctiveness. Here, we report two cases involving Japanese women aged 59 years, both with A-DLBCL with the hallmark cell appearance and both indistinguishable from common and giant cell-rich patterns, respectively, of anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma. Case 1 was immunohistochemically positive for CD20, CD79a and OCT-2 but not for the other pan-B-cell markers, CD30 and ALK. Case 2 showed CD20 and CD30 positivity for 50% and 20% of tumor cells in addition to strong expression of p53 and MYC. Both were positive for fascin without Epstein-Barr virus association. Our cases provide additional support for the earlier reports that A-DLBCL exhibits clinicopathologic features distinct from ordinal diffuse large B-cell lymphoma (DLBCL), and documented its broader morphologic diversity than previously recognized. They also shed light on the unique feature of absent expression of pan-B-cell markers except for CD20 and CD79a, suggesting that A-DLBCL may biologically mimic a gray zone or intermediate lymphoma between DLBCL and classic Hodgkin lymphoma.

The aim of this study was to compare the accuracy of the QuantStudio 3D Digital polymerase chain reaction (dPCR) system and a PCR-based next generation sequencing (NGS) system for detecting a secondary mutation in the epidermal growth factor receptor (EGFR) gene T790M in non-small cell lung cancer (NSCLC) patients previously diagnosed with EGFR-activating mutations. Twenty-five patients with NSCLC previously treated with EGFR-TKIs were examined. The patients were treated daily with either erlotinib or gefitinib. New biopsies, followed by DNA sequencing on an Ion Torrent systems using the Ion Torrent AmpliSeq Cancer Hotspot Panel and dPCR were performed. A comparison of NGS, sensitive PCR, and dPCR revealed that the sensitivities of NGS and dPCR were similar in this study. As well, T790M was detected in as low as about 5% of mutant allelic frequencies, which represented 5% of the total reads on site mapped reads in NGS and greater than 5% of the dPCR reads, which represented mutant and wild type copies. The strategy in which NGS sequencing is followed by revealed acquired mutation with dPCR may be a reasonable one. We demonstrated the utility of combining NGS and dPCR as a tool for monitoring T790M. NGS and dPCR with formalin-fixed paraffin-embedded (FFPE) specimens might become a standard genomic test for exploring acquired resistance to targeted molecular medicines.

BACKGROUND Major salivary gland cancers (M-SGCs) are rare, and have distinct heterogeneous histopathological subtypes. To the authors' knowledge, no consistent evidence of an association between cigarette smoking and the risk of M-SGCs has appeared to date. Furthermore, evidence of potential heterogeneity in the impact of smoking on histopathological subtypes is scarce, despite the fact that the histopathological subtypes of M-SGC exhibit different genetic features. METHODS The authors conducted a case-control study to investigate the association between smoking and M-SGC by histopathological subtype. Cases were 81 patients with M-SGCs and the controls were 810 age-matched and sex-matched first-visit outpatients without cancer treated at Aichi Cancer Center Hospital from 1988 to 2005. Odds ratios (OR) and 95% confidence intervals (95% CI) were assessed by conditional logistic regression analysis with adjustment for potential confounders. RESULTS Smoking was found to be associated with a significantly increased risk of M-SGC overall, with an OR of 3.45 (95% CI, 1.58-7.51; P =.001) for heavy smokers compared with never-smokers. A significant dose-response relationship was observed (P for trend, .001). When stratified by histological subtype, no obvious impact of smoking was observed among patients with mucoepidermoid carcinoma (MEC). In contrast, smoking demonstrated a significantly increased risk of M-SGCs other than MEC, with an OR of 5.15 (95% CI, 2.06-12.87; P

Aims Cancer/testis antigens (CTAs) are detected in cancer cells but not in healthy normal tissues, with the exception of gametogenic tissues. CTAs are highly immunogenic proteins, and thus represent ideal targets for cytotoxic T-lymphocyte-mediated specific immune therapy. The aim of this study was to screen CTA expression in various types of salivary gland carcinoma and to clarify clinicopathological significance of MAGE-A and NY-ESO-1 expression in adenoid cystic carcinomas (AdCCs) of the salivary gland, which is one of the most common salivary gland carcinomas, and usually has a fatal outcome. Methods and results We used immunohistochemistry to examine the expression of four CTAs (MAGE-A, NY-ESO-1, CT7, and GAGE7) in various types of salivary gland carcinoma (n = 95). When carcinoma cases were divided into low-grade and intermediate/high-grade types, NY-ESO-1 and CT7 were expressed more frequently in intermediate/high-grade carcinomas. We then focused on MAGE-A and NY-ESO-1 expression in a large cohort of adenoid cystic carcinomas (AdCCs) (n = 46). MAGE-A and NY-ESO-1 were frequently expressed in AdCC; specifically, MAGE-A was expressed in >60% of the AdCC cases. MAGE-A expression and tumour site (minor salivary gland) were identified as independent risk factors for locoregional tumour recurrence. Conclusions These findings suggest that CTAs may be expressed in a variety of salivary gland carcinomas, especially in those with higher histological grades. In addition, MAGE-A, which is frequently expressed in AdCC cases, may be a useful prognostic factor for poorer locoregional recurrence-free survival.

Microglandular adenosis (MGA) is a rare proliferative lesion of the breast composed of small glands lacking myoepithelial cells and lined by S100-positive, oestrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and HER2-negative epithelial cells. There is evidence to suggest that MGA may constitute a non-obligate precursor of triple-negative breast cancer (TNBC). We sought to define the genomic landscape of pure MGA and of MGA, atypical MGA (AMGA) and associated TNBCs, and to determine whether synchronous MGA, AMGA, and TNBCs would be clonally related. Two pure MGAs and eight cases of MGA and/or AMGA associated with in situ or invasive TNBC were collected, microdissected, and subjected to massively parallel sequencing targeting all coding regions of 236 genes recurrently mutated in breast cancer or related to DNA repair. Pure MGAs lacked clonal non-synonymous somatic mutations and displayed limited copy number alterations (CNAs); conversely, all MGAs (n = 7) and AMGAs (n = 3) associated with TNBC harboured at least one somatic non-synonymous mutation (range 3-14 and 1-10, respectively). In all cases where TNBCs were analyzed, identical TP53 mutations and similar patterns of gene CNAs were found in the MGA and/or AMGA and in the associated TNBC. In the MGA/AMGA associated with TNBC lacking TP53 mutations, somatic mutations affecting PI3K pathway-related genes (eg PTEN, PIK3CA, and INPP4B) and tyrosine kinase receptor signalling-related genes (eg ERBB3 and FGFR2) were identified. At diagnosis, MGAs associated with TNBC were found to display subclonal populations, and clonal shifts in the progression from MGA to AMGA and/or to TNBC were observed. Our results demonstrate the heterogeneity of MGAs, and that MGAs associated with TNBC, but not necessarily pure MGAs, are genetically advanced, clonal, and neoplastic lesions harbouring recurrent mutations in TP53 and/or other cancer genes, supporting the notion that a subset of MGAs and AMGAs may constitute non-obligate precursors of TNBCs.

Background The aim of this study was to examine the associations between postoperative clinicopathological features of intraductal papillary mucinous neoplasm (IPMN) and recurrence over a long follow-up period. Methods We retrospectively assessed 153 IPMN patients who underwent resection. Results The resected tumors showed low/intermediate-grade dysplasia (LGD/IGD), high-grade dysplasia (HGD), T1a (stromal invasion ≤5 mm), and invasive intraductal papillary mucinous carcinoma (IPMC), in 54.9%, 22.2%, 4.6%, and 18.3% of patients, respectively. The median follow-up period after surgery was 46.4 (6.0–216.3) months, with an overall recurrence rate of 17.0%; the recurrence rates by histological type were 6.0%, 5.9%, 42.9%, and 57.1% for LGD/IGD, HGD, T1a, and invasive IPMC, respectively. Multivariate analysis revealed that recurrences related with tumor location, mural nodule size, presence of invasive cancer, lymph node metastasis, IPMN in the remnant pancreas, and main pancreatic duct dilatation after surgery. Recurrence occurred within the remnant pancreas in all LGD-T1a patients and as extrapancreatic metastasis in all patients with invasive IPMC. Of the total recurrences, 15.4% occurred over 5 years postoperatively. Conclusions The postoperative follow-up protocol for patients with LGD-T1a should be similar to non-resected IPMN, and that for invasive IPMC should be the same as for pancreatic ductal adenocarcinoma patients.

Intratumoral heterogeneity of HER2 expression in the metastatic foci of HER2-positive advanced gastric cancer remains unclear. In this study, we compared HER2 expression between primary and metastatic tumors in HER2-positive three autopsied cases and one resected case with multiple organ metastases by immunohistochemistry (IHC) and dual color in situ hybridization (DISH). All four cases judged positive (IHC3+) at the primary tumor tissues showed varying HER2 gene amplification (GA) status. One homogeneously HER2-positive autopsied case (Case 1) and one intratumorally heterogeneous positive resected case (Case 2) with high GA showed a homogeneous positive staining pattern in all the metastatic foci. One heterogeneously HER2-positive autopsied case (Case 3) with low GA showed a partially heterogeneous HER2 staining pattern in all the metastatic foci. In contrast, one heterogeneously HER2-positive autopsied case (Case 4) with equivocal GA showed a completely heterogeneous HER2 staining pattern in the metastatic foci. These results indicate that HER2-positive gastric cancers with low to high GA at the primary tumor show substantially homogeneous HER2 overexpression in the metastatic foci, whereas HER2-positive gastric cancers with equivocal GA expressed HER2 heterogeneously within the metastatic tumor, suggesting that metastatic foci of the latter HER2-positive cases would be potentially resistant to trastuzumab.

The Japanese guidelines for the testing of KRAS mutations in colorectal cancer have been used for the past 5 years. However, new findings of RAS (KRAS/NRAS) mutations that can further predict the therapeutic effects of anti-epidermal growth factor receptor (EGFR) antibody therapy necessitated a revision of the guidelines. The revised guidelines included the following five basic requirements for RAS mutation testing to highlight a patient group in which anti-EGFR antibody therapy may be ineffective: First, anti-EGFR antibody therapy may not offer survival benefit and/or tumor shrinkage to patients with expanded RAS mutations. Thus, current methods to detect KRAS exon 2 (codons 12 and 13) mutations are insufficient for selecting appropriate candidates for this therapy. Additional testing of extended KRAS/NRAS mutations is recommended. Second, repeated tests are not required for the detection; tissue materials of either primary or metastatic lesions are applicable for RAS mutation testing. Evaluating RAS mutations prior to anti-EGFR antibody therapy is recommended. Third, direct sequencing with manual dissection or allele-specific PCR-based methods is currently applicable for RAS mutation testing. Fourth, thinly sliced sections of formalin-fixed, paraffin-embedded tissue blocks are applicable for RAS mutation testing. One section stained with H&E should be provided to histologically determine whether the tissue contains sufficient amount of tumor cells for testing. Finally, RAS mutation testing must be performed in laboratories with appropriate testing procedures and specimen management practices.

A perivascular epithelioid cell tumor (PEComa) is a peculiar growth defined as a mesenchymal tumor composed of histologically and immunohistochemically distinct perivascular epithelioid cells (PECs). Because neither normal counterparts nor precursor lesions of PEComa have been identified, we examined minute PEC nests, ranged from 0.8 mm to 10 mm, to investigate the possible origin of the PEComa. We examined a total of 80 677 para-aortic and pelvic lymph nodes that were systematically dissected from 1656 patients for gynecological malignancies. The identified lesions were confirmed immunohistochemically with multiple PEC markers, including smooth muscle actin, HMB45, melan-A, MiTF, ER and PgR. A total of 66 minute PEC nests were found in 21 patients (1.3% of the total population) with an average frequency of 3.1 lesions per patient. In cases of multiple involvement, 11 of 13 nests were located at the same level of multiple lymph node or on continuous levels. The lesions were preferentially distributed at the level of para-aortic and high pelvic lymph nodes. All nests were positive for actin and HMB45, whereas the other markers were positive with varying frequencies. The minute PEC nests may be associated with the possible normal counterpart of PEComas.

Background and Aim Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor of the gastrointestinal tract. However, little is known about the clinical presentation of GIST, especially small lesions. The purpose of the present study was to clarify the efficacy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for the diagnosis of GIST and to determine its clinical course. Methods Pathological and clinical records of GIST extracted from our institutional database between 1996 and 2012 were reviewed. All GIST cases were diagnosed pathologically by surgical specimen or EUS-FNA. To examine the efficacy of EUS-FNA for the diagnosis of GIST, the pathological findings of EUS-FNA were compared with the surgical findings from resected cases. Next, to clarify the clinical presentation of GIST, imaging findings and changes in tumor size over time were evaluated in follow up. Results Of 84 cases of GIST, 67 were resected surgically after EUS-FNA; tumor size was

Objective: The excessive consumption of confectionery might have adverse effects on human health. To screen genetic factors associated with confectionery-intake frequency, a genome-wide association study (GWAS) in Japan was conducted. Design and Methods: For the discovery phase (stage 1), we conducted a GWAS of 939 noncancer patients in a cancer hospital. Additive models were used to test associations between genotypes of approximately 500,000 single-nucleotide polymorphisms (SNPs) and the confectionery-intake score (based on intake frequency). We followed-up association signals with P 0.01 in stage 1 by genotyping the SNPs of 4,491 participants in a cross-sectional study within a cohort (replication phase [stage 2]). Results: We identified 12 SNPs in stage 1 that were potentially related to confectionery intake. In stage 2, this association was replicated for one SNP (rs822396; P = 0.049 for stage 2 and 4.2 × 10−5 for stage 1+2) in intron 1 of the ADIPOQ gene, which encodes the adipokine adiponectin. Conclusions: Given the biological plausibility and previous relevant findings, the association of an SNP in the ADIPOQ gene with a preference for confectionery is worthy of follow-up and provides a good working hypothesis for experimental testing.

The RET finger protein (RFP) is a transcription factor belonging to the TRIM (tripartite motif) superfamily of proteins. RFP is expressed in a variety of human and rodent tumor cell lines and in several kinds of human cancer. Expression of RFP is associated with prognosis of colon and endometrial cancers. In the present study, we evaluated the expression of RFP in lung cancer and assessed its clinical significance. Tissue microarrays were constructed from 108 cases of lung cancer, and the sections were analyzed for RFP expression by immunohistochemistry. RFP expression was detected in the nucleus in 66.7% of lung cancer tissues examined. RFP expression was statistically significantly associated with thyroid transcription factor 1 (TTF-1) expression (P= 0.028). However, no significant association was observed between RFP expression and other clinicopathological or genetic factors, including epidermal growth factor receptor (EGFR) mutations. Interestingly, we found that RFP expression correlated with poor prognosis in patients with EGFR mutations (P= 0.032). Our results suggest that RFP has a role in mutated EGFR signaling and that RFP status may be a prognostic factor for lung cancer with EGFR mutations.

Obtaining histological evidence of gallbladder carcinoma (GBC) is difficult due to its extraductal nature, and pathological confirmation remains challenging. We compared the diagnostic value and safety of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) with endoscopic retrograde cholangiography (ERC) in patients with suspected GBC.Eighty-three patients with GBC were evaluated. Prior to definitive management, pathological evidence of GBC was obtained through either ERC cytopathologic sampling (n = 33), EUS-FNA (n = 24) or both (n = 26).Among the 83 patients, 59 (71.0%) with biliary obstruction were sampled using ERC with 47.4% (28/59) sensitivity. In 19 of the remaining 31 cases, EUS-FNA sampling had 100% diagnostic sensitivity. Likewise, 50 (60.2%) of the 83 patients with suspected GBC underwent EUS-FNA of regional lymph nodes or the gallbladder (GB) mass itself with 94.8% sensitivity. The overall diagnostic sensitivity rates of ERC and EUS-FNA were 47.4 and 96%, respectively (P 0.001). Post-procedural complications were seen in 6.7% of the ERC group (4/59, all were mild pancreatitis), and in none of the EUS-FNA group (P = 0.10).Gallbladder carcinoma sampling using ERC and EUS-FNA should be incorporated into the diagnostic workup of GB lesions as complementary tools, and EUS-FNA should be applied in the setting of failed or not indicated ERC.

Histone H1, one of the histone superfamilies, is known to determine chromatin structure and alter gene expression. It also contributes to regulation of cell proliferation in breast cancer. We hypothesized a similar association in prostate cancer, and therefore examined relationships between histone H1 expression and Gleason pattern, Ki-67 and androgen receptor levels in a series of prostate cancer tissues and cell lines. Histone H1 positive cancer cells increased with the Gleason pattern. Gleason pattern 3 tumors were divided into two groups, one with high histone H1 positivity (H1-high cases, 60-100% positivity) and the other with low histone H1 positivity (H1-low cases, 0-20% positivity). Ki-67 or androgen receptor positivity in H1-high cases was significantly higher than in H1-low cases. PC3 cells demonstrated more frequent histone H1 and Ki-67 positivity as compared to LNCaP cells. Silencing of histone H1 by siRNA transfection significantly reduced cell proliferation in LNCaP and PC3. These findings suggest that histone H1 expression is associated with the Gleason pattern, cell proliferation and androgen receptor expression in prostate cancers.

We describe a patient who was diagnosed with classical Hodgkin lymphoma (CHL) at 67-years-old and peripheral T-cell lymphoma, not otherwise specified (PTCL) at 76-years-old, and died 5 months later. Both tumors showed prominent epithelioid cell reaction admixed with neoplastic cells. Hodgkin and Reed-Sternberg cells in the swollen lymph node were positive for CD30 and EBV-encoded RNA (EBER). PTCL cells in the skin tumor were positive for cytoplasmic CD3e, CD4 and EBER. A rearrangement band of the T-cell receptor gene was detected in the skin tumor. This case is the first documented EBV-associated composite lymphoma composed of CHL and PTCL. The patient may show the possibility that both EBV infection and/or immunodeficiency induce the development of CHL and PTCL.

The insulin-like growth factor (IGF) signaling system plays a central role in cellular growth, differentiation and proliferation. Although the association between IGF1 gene polymorphisms and cancer risk has been evaluated for several carcinomas, this association has not yet been examined for stomach cancer. We investigated the association between IGF1 polymorphisms and the risk of stomach cancer in a Japanese population. A total of 703 patients with stomach cancer and 1462 non-cancer control subjects were enrolled in this case–control study. Associations between polymorphisms of 10 IGF1 loci and the risk of stomach cancer were evaluated using odds ratios (OR) and 95% confidence intervals (CI) in multiple logistic regression models. We observed that the C allele in rs1520220 and the G allele in rs4764887 were significantly associated with stomach cancer risk in the per-allele model after adjusting for other risk factors (OR: 1.14 [95% CI: 1.00–1.30] and OR: 1.18 [95% CI: 1.02-1.36], respectively). We also observed a positive and dose-dependent association between the number of risk alleles and stomach cancer risk (P-trend: 0.019) when examining the two loci in the same model. These associations were still seen after adjusting for potential confounders, including sex, age, smoking status, history of diabetes and family history of stomach cancer. We did not find any significant interaction between these factors and the number of risk alleles. In conclusion, we observed a significant association between IGF1 polymorphisms and stomach cancer risk among a Japanese population. Examination of the biological significance of IGF1 is warranted. (Cancer Sci 2011; 102: 2231–2235)

We previously identified PSMD2, a subunit of the 19S regulatory complex of proteasomes, as a constituent of a signature associated with the acquisition of metastatic phenotype and poor prognosis in lung cancers. In the present study, we found that knockdown of PSMD2 decreased proteasome activity, and induced growth inhibition and apoptosis in lung cancer cell lines. These effects of siRNA-mediated PSMD2 inhibition were associated with changes in the balance between phosphorylated AKT and p38, as well as with induction of p21. In addition, patients with higher PSMD2 expression had poorer prognosis and a small fraction of lung cancer specimens carried increased copies of PSMD2. Notably, our findings clearly illustrate that lung adenocarcinomas can be divided into two groups; those with and without general upregulation of proteasome pathway genes including PSMD2. This general upregulation was significantly more prevalent in the non-terminal respiratory unit (non-TRU)-type, a recently proposed genetically and clinicopathologically relevant expression profile-defined classification of adenocarcinomas (P

We describe a 66-year-old woman with Epstein-Barr virus-associated lymphoproliferative disorder with lung and gastric tumors. We identified two lung tumors measuring 13 and 20 mm in diameter that consisted of CD30-, CD15-, and CD20-positive Hodgkin- and Reed-Sternberg-like cells and heterogeneous cellular infiltrates in a pronounced nodular pattern, with necrosis and vasculitis, diagnosed as nodular sclerosis classical Hodgkin lymphoma. A gastric tumor showed low-grade extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue type. Neoplastic cells in all tumors expressed Epstein-Barr virus-encoded RNA based on in situ hybridization. The present case is a rare composite lymphoma arising from different extranodal organs, associated with EBV infection. Her medical history included gamma-knife therapy for clinical diagnosis with a suspicion of cerebral lymphoma.

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has enabled clinicians to histologically diagnose pancreatic tumors. However, EUS-FNA specimens often result in tiny fragmented tissues, so auxiliary utilities are necessary. Using immunostaining of CK7, CDX2, neuroendocrine markers and KRAS mutation analysis, we examined 57 FNA cell block sections and 61 surgically-resected specimens (25 invasive ductal carcinomas, 25 endocrine tumors, and 11 acinar cell tumors). In the majority of the matched pairs, the diagnoses between EUS-FNA and surgical specimens were concordant using the following criteria: neuroendocrine markers negative, CK7 positive, and mutated KRAS gene for invasive ductal carcinomas; neuroendocrine markers diffusely positive, CK7 and CDX2 negative, and wild-type KRAS gene for well-differentiated endocrine tumors; and neuroendocrine markers no more than focal positive, CK7 and CDX2 with various staining patterns, and wild-type KRAS gene for acinar cell carcinomas. Expression of CK7 and/or CDX2 in addition to KRAS mutations were occasionally seen in endocrine carcinomas, but not in well-differentiated endocrine tumors, suggesting that ductal differentiation in an endocrine tumor may be a predictor of aggressive disease. The usefulness of these markers was confirmed using 13 additional pancreatic tumors, prospectively. Although minimal in selection, these markers are helpful in making diagnosis from EUS-FNA specimens of the major pancreatic tumors.

Some Japanese exhibit facial flushing after drinking alcohol. Facial flushing was considered to be caused by acetaldehydemia. The concentration of blood acetaldehyde was concerned with the catalytic activity of acetaldehyde dehydrogenase (ALDH). Acetaldehyde dehydrogenase (ALDH)-2 polymorphism (rs671, Glu504Lys) was known to be associated with upper aerodigestive tract (UAT) cancer due to modulation of ALDH2 enzyme activity. It remains controversial whether facial flushing is useful in predicting UAT cancer risk as a surrogate marker of ALDH2 polymorphism. We conducted a case-control study to assess the risk of UAT cancer and facial flushing and ALDH2 polymorphism. Cases and controls were 585 UAT cancer patients and matched 1170 noncancer outpatients of Aichi Cancer Center Hospital. Information on facial flushing and other lifestyle factors was collected via a self-administered questionnaire. Association between facial flushing, polymorphism, and UAT cancer was assessed by odds ratios and 95% confidence intervals by using conditional logistic regression models. The facial flushing had no significant association with UAT cancer, although ALDH2 Lys allele was significantly associated with UAT cancer. No significant interaction between facial flushing and alcohol consumption was observed in this study, whereas ALDH2 Lys allele had significant association with UAT cancer. The misclassification between facial flushing and ALDH2 genotype was observed in 18% of controls with ALDH2 Glu/Glu genotype and in 16% of controls with ALDH2 Glu/Lys genotype. Facial flushing was less useful to predict UAT cancer risk than genotyping ALDH2 polymorphism.

Aberrant DNA methylation is involved in colon carcinogenesis. Although the CpG island methylator phenotype (CIMP) is defined as a subset of colorectal cancers (CRCs) with remarkably high levels of DNA methylation, it is not known whether epigenetic processes are also involved in CIMP-negative tumors. We analyzed the DNA methylation profiles of 94 CRCs and their corresponding normal-appearing colonic mucosa with 11 different markers, including the five classical CIMP markers. The CIMP markers were frequently methylated in proximal CRCs (p < 0.01); however, RASSF1A methylation levels were significantly higher in distal CRCs, the majority of which are CIMP-negative (p < 0.05). Similarly, methylation levels of RASSF1A and SFRP1 in the normal-appearing mucosae of distal CRC cases were significantly higher than those in the proximal CRC cases (p < 0.05). They were also positively correlated with age (RASSF1A, p < 0.01; SFRP1, p < 0.01). Microarray-based genome-wide DNA methylation analysis of 18 CRCs revealed that 168 genes and 720 genes were preferentially methylated in CIMP-negative distal CRCs and CIMP-positive CRCs, respectively. Interestingly, more than half of the hypermethylated genes in CIMP-negative distal CRCs were also methylated in the normal-appearing mucosae, indicating that hypermethylation in CIMP-negative distal CRCs is more closely associated with age-related methylation. By contrast, more than 60% of the hypermethylated genes in CIMP-positive proximal CRCs were cancer specific (p < 0.01). These data altogether suggest that CpG island promoters appear to be methylated in different ways depending on location, a finding which may imply the presence of different mechanisms for the acquisition of epigenetic changes during colon tumorigenesis.

Hepatic giant cell tumor is extremely rare, and only five cases have been reported of overt hepatocellular carcinoma, thus its histogenesis is controversial. Herein is reported a case of simultaneous hepatocellular carcinoma and osteoclast-like giant cell tumor in a single tumor. A liver tumor was found in a 74-year-old woman. Histologically the tumor consisted of two distinct components: mononuclear and multinuclear giant cells with osteoclastic giant cells, and a conventional hepatocellular carcinoma. The boundary between the two components showed transitional features. Immunohistochemistry showed that the osteoclast-like giant cells were CD68 and vimentin positive, but cytokeratin and AFP negative, while spindle-shaped cells were positive only for vimentin. In a portion of the hepatocellular carcinoma the cells were cytokeratin-8 and AFP positive. Ki-67 positivity was 10% for the hepatocellular carcinoma, 60% for the spindle-shaped cells, and 0% for the giant cells. It is possible that the tumor might have had a hepatocellular carcinoma origin, given the more highly proliferative sarcomatous changes and reactive osteoclast-like cells. This case provides a clue to the histogenesis of hepatic giant cell tumors.

We examined the diagnostic accuracy of the cumulative smoking dose for identifying the epidermal growth factor receptor (EGFR) exon 19 deletion and L858R mutation among Japanese patients with non-small-cell lung cancer (NSCLC). EGFR mutations in exon 19 and exon 21 were determined in 1001 NSCLC patients. A receiver–operating characteristic (ROC) curve methodology was applied to estimate the diagnostic accuracy. EGFR mutations were detected in 314 patients (31.4%). A cumulative smoking dose of less than 13 pack-years (PY) was the optimal cut-off point for predicting a positive EGFR mutation status, producing a balance between the sensitivity (73.5%) and the specificity (77%). The area under the ROC curve was 0.77, indicating that the smoking dose had a moderate diagnostic accuracy. The median survival time or the median progression-free survival time of patients who had smoked less than 13 pack-years (PY) were 18.6 and 6.3 months, respectively, while those of patients with equal to or more than 13 PY were 9.6 and 2.4 months, respectively. The overall survival (OS) and progression-free survival (PFS) rates were significantly different between the two groups (OS: hazard ratio [HR] = 0.64, 95% confidence interval [CI] = 0.51–0.80, P = 0.0001) (PFS: HR = 0.58, 95% CI = 0.47–0.71, P

Aim: Differential diagnosis, including the respective distinctions between benign and malignant tumors, follicular and papillary neoplasms, and follicular adenoma and follicular carcinoma, are always required in clinical practice, because therapeutic strategy largely depends on the diagnosis made. Methods: The present study describes a novel approach to obtaining clinically useful markers by means of the simultaneous comparison of multiple molecules using tissue array analysis. The markers examined in this study include galectin-3, CD44v6, p53, HBME-1, maspin and S100A4, which were reportedly useful for making these distinctions in association with metastasis and invasion. A total of 45 cases of thyroid tumors (seven adenomatous goiters, 16 follicular adenomas, 12 follicular carcinomas and 10 papillary carcinomas) were analyzed. Results: The results demonstrated the following suggestive phenotypes: galectin-3-, HBME-1- and maspin+ as benign lesions, galection-3-, HBME-1+ and maspin- as follicular carcinoma, and galectin-3+, HBME-1+ and maspin+ as papillary carcinoma. Conclusions: The expression of the molecules was assessed in each case and the expression profiles were compared. Useful multiple molecules were selected for each distinction and were correlated with each other. To understand the complex relationship, a logistic regression model was constructed. These results suggested that combined analysis of multiple molecules enhanced the differential diagnostic accuracy.

Background and Objectives The distinction of primary lung from metastatic breast cancer is crucial in patients presenting with a solitary pulmonary nodule after mastectomy, because treatment strategies are completely different. Definitive diagnosis of these nodules, however, is often difficult. We assessed the feasibility of our diagnostic approach for these nodules and estimated the frequency of primary lung cancer occurrence in patients after mastectomy. Methods We evaluated solitary pulmonary nodules appearing in 48 patients after mastectomy. For histological examination, CT-guided needle aspiration biopsy (CT-NAB) or trans-bronchial lung biopsy (TBLB) was performed. Besides conventional morphopathological examination, differential diagnosis was performed by immunohistochemical examination and evaluation using a molecular marker (mammaglobin 1). Results Biopsy specimens were obtained using minimally invasive methods, namely CT-NAB and TBLB, in 91.7% of patients. From 48 patients, differential diagnosis was obtained by morphopathological methods alone in 32, and by immunohistochemical and molecular marker examination in the remaining 16. Final diagnosis was metastatic breast and primary lung cancer in 40 (83.3%) and 8 patients (16.7%), respectively. Conclusions Our results show the clinical feasibility of our stepwise approach to the differential diagnosis of primary lung cancer and breast cancer relapse presenting as a solitary nodule in patients after mastectomy. J. Surg. Oncol. 2008;98:510–514. © 2008 Wiley-Liss, Inc.

Background and objective: Expression of genes involved in DNA repair and/or DNA synthesis, including ribonucleotide reductase M1 (RRM1) and excision repair cross-complementation 1 (ERCC1) has been reported to be associated with chemosensitivity to platinum agents and gemcitabine. The aim of this study was to test whether similar associations would be seen between mRNA expression for the RRM1, ERCC1 and ERCC2 genes and in vitro chemosensitivity in lung cancer. Methods: Using a panel of 20 lung cancer cell lines, including 15 NSCLC and 5 small cell lung cancers (SCLC), the mRNA expression levels for the RRM1, ERCC1 and ERCC2 genes were examined by quantitative real-time reverse transcription PCR. The in vitro cytotoxicity of cisplatin, carboplatin and gemcitabine was assessed using a tetrazolium-based colorimetric assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide (MTT) assay). Results: Significantly, higher RRM1 mRNA expression was found in SCLC compared with NSCLC. However, there were no correlations between mRNA expression of the ERCC1, ERCC2 and RRM1 genes and chemosensitivity to cisplatin, carboplatin or gemcitabine. Conclusions: These in vitro results suggest that further studies are needed to evaluate the expression of the RRM1, ERCC1 and ERCC2 genes as predictive biomarkers for sensitivity to platinum agents and gemcitabine.

Approximately 70% of gastric mucosa-associated lymphoid tissue (MALT) lymphomas can be successfully treated with H. pylori eradication. The translocation t(11;18)(q21;q21) characteristic of MALT lymphoma is recognized as a marker for H. pylori independency, but this marker is found in only a half of the MALT lymphomas resistant to H. pylori eradication. Detailed analyses of the genomic features of eradication resistant as well as responsive groups are important for understanding their molecular basis. We performed array-based comparative genomic hybridization (array-CGH) for 29 gastric MALT lymphomas treated with H. pylori eradication. These comprised ten cases of t(11;18) positive MALT, nine cases of t(11;18) negative MALT with H. pylori dependency, and ten cases of t(11;18) negative MALT with H. pylori independency. Array-CGH analysis demonstrated that no significant genetic alterations were found in t(11;18) positive MALT lymphomas, but numerous genomic alterations were detected in t(11;18) negative MALT lymphomas. Many of these alterations were similar to those found in diffuse large B-cell lymphoma with trisomy 3 being the most recurrent alteration. Within the t(11;18) negative MALT lymphoma without large cell components group, genomic imbalances occurred more frequently in the H. pylori independent than in the H. pylori dependent group (P = 0.02). Genomic imbalances are associated with H. pylori independency in t(11;18) negative gastric MALT lymphomas. They may thus play an important role in the development of H. pylori independency.

In 2004, two groups reported somatic mutations in the gene for the epidermal growth factor receptor (EGFR) in patients with non-small cell lung cancer (NSCLC), which were highly correlated with the clinical response to the anticancer drug, gefitinib. Since then, a tremendous amount of knowledge has accumulated, and sheds light on significant oncological properties as well as the clinical relevance of this mutation, which could be applicable to other malignancies. The EGFR mutations are distributed throughout the kinase domain, but a deletion in exon 19 and the point mutation L858R in exon 21 account for approximately 90%, which confer a greater response to gefitinib treatment, compared with other types of EGFR mutations. These EGFR mutations in the tyrosine kinase domain are seldom acquired in cancers of the other organs and the mutations preferentially involve a subset of lung cancers, which are clinicopathologically characterized by female sex, non-smoking, adenocarcinoma histology and East Asian ethnicity. In Japan, the EGFR mutations are detected in approximately 30% of overall NSCLC and approximately 40% of surgically resected adenocarcinomas. The morphological features of adenocarcinomas harboring the mutations were reported to be frequent in those with bronchioloalveolar features, but it is suggested that the cellular lineage of the putative original cells of the cancers refines the subset more clearly. In the present study the current knowledge of EGFR mutations is reviewed, insights from which raise many further questions, and thus suggest new directions for future research.

In contrast to the clear oncogenic role of cyclins D1 and D2, cyclin D3 is suggested to have a role in the initiation and/or maintenance of differentiation in a lineage-associated manner in addition to its basic role in proliferation. Recently, it has been reported that in cyclin D3-deficient mice, normal expansion of T lymphocytes is impaired because of maturation arrest at the double-negative thymocyte stage, suggesting a crucial role for cyclin D3 in early T-cell development. Therefore, cyclin D3 expression was examined in 36 human precursor T-lymphoblastic leukemia/lymphomas (T-LBLL), a neoplastic counterpart of T cells at the early developmental stages of differentiation. Using a standard panel of differentiation markers, all T-LBLL were categorized into four stages according to differentiation: progenitor, double-negative, double-positive, and single-positive stages. Cyclin D3 expression was initiated at the boundary between double-negative and double-positive stages, and was sustained in the single-positive stage. T-cell receptor was expressed simultaneously with cyclin D3, whereas CD79a expression was specific in the double-negative stage, and thus it was inversely correlated with that of cyclin D3. Taken together with the crucial and non-redundant role in T-cell development in mice, this molecule is suggested to play an important role in human T-cell development.

The present study aimed to assess the impact of smoking and sex for the risk of non-small-cell lung cancer (NSCLC) with or without epidermal growth factor receptor (EGFR) mutation. We conducted a case-control study using 152 patients with EGFR-mutated (EGFRmut) NSCLC, 283 with EGFR-wild-type (EGFRwt) NSCLC and 2175 age- and sex-frequency-matched controls. Smoking was a significant risk factor for EGFRwt NSCLC (odds ratio [OR] for ever-smokers, 4.05; 95% confidence interval [CI], 2.79-5.88) but not for EGFRmut NSCLC (OR, 0.73; CI, 0.46-1.14). Sex did not affect this association. The association was observed consistently with other smoking-related parameters including pack-years. Sex was the sole risk factor for EGFRmut NSCLC (OR for women relative to men, 2.19; CI, 1.41-3.39) and there was no significant interaction between women and smoking. In contrast, sex, smoking and their interaction were significant in EGFRwt NSCLC. The impact of sex on EGFR mutation status was assessed by several indicators of reproductive history among women. Total fertile years showed a significant positive association with EGFRmut NSCLC but not with EGFRwt NSCLC. Other indicators showed similar trends and this result may partly explain the sexual difference in the acquisition of EGFR mutation. In conclusion, our case-control study clearly demonstrated that the impacts of smoking and sex on the risk of EGFRmut NSCLC are different from those for EGFRwt NSCLC. Further epidemiological evaluation is warranted.

BACKGROUND Although ascites cytology is important for therapeutic strategies, it is difficult to distinguish cancer infiltration from reactive mesothelial proliferation in some patients. In this study, the authors applied CDX2 immunocytochemistry to improve diagnostic accuracy. METHODS The authors examined the distribution of CDX2 expression in carcinoma specimens using paraffin-embedded tissues from various organs from 549 cancer patients. CDX2 immunostaining was applied to the 116 ascites specimens. RESULTS CDX2 expression was detected in a restricted range of cancers, with the vast majority of them originating from the gastrointestinal tract and pancreas. When applied to ascites specimens, no positive reactions were detected in any of the 81 cytology-negative and molecular genetic analysis-negative specimens. By contrast, 28 of 35 specimens diagnosed as suspicious for malignancy or malignancy showed a positive reaction. Furthermore, the authors found that a nuclear-positive reaction was easily evaluated, even with a high level of background staining, and single cancer cells in 106 normal cells could be detected. CONCLUSION Results suggest that CDX2 is a specific and sensitive marker to detect gastrointestinal and pancreatic malignancies in ascites cytology. Cancer (Cancer Cytopathol) 2006. © 2006 American Cancer Society.

Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography-guided fine-needle aspiration biopsy (EUS-FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS-FNAB was performed was 62 years (range 26–82 years) and the median follow-up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS-FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed.