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Tumor deposits (TD) are irregular discrete tumor masses in adipose tissue, discontinuous from the primary tumor, that are described in various cancers. The incidence and/or prognostic value of TD in breast carcinomas have not been studied so far. We reevaluated 145 breast cancer patients, diagnosed and treated between 2001 and 2006 at our institution for the presence and incidence of TD. Histologic type, grade, size of the primary tumor, estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 status of the tumor, and presence of peritumoral lymphovascular invasion were included in the data. TD were detected in 42 cases (29.0%). The mean age of the patients was 52.2 years (27-82). Most patients (79.3%) had either invasive carcinoma of no special type (NST) or invasive lobular carcinoma, and most tumors (86.9%) were either grade 2 or 3. After excluding TD from the number of metastatic lymph nodes, the pN status of 9 patients changed. Univariate analysis of 110 patients with follow-up information revealed that the new pN status (p = 0.036), presence of local recurrence (p = 0.016) and TD (p = 0.003) were significantly correlated with distant metastases. The median follow-up of the patients was 84 months (5-161), 10-year disease-free survival and overall survival were 67.2% and 73.7%, respectively. In multivariate analysis, presence of TD remained independently associated with distant metastasis (p = 0.002). The probability of distant metastasis was 3.3 times higher in patients with TD. These results emphasize that TD are present in breast cancer patients, and that their presence should warn the clinician in terms of possible distant metastasis. Therefore, presence of TD, the evaluation of which is neither time consuming nor require sophisticated methods, should be included in pathology reports.

Angiocentric glioma is an epileptogenic, infiltrative, low grade glial tumor, with ependymal and astrocytic differentiation, most commonly seen in young adults and the pediatric age group. Herein we report a case of 21-year-old male patient who presented with fever and pharmaco-resistant seizures. Computed tomography revealed an iso-dense mass lesion in the gyrus rectus of the left frontal lobe. On magnetic resonance imaging the mass was hyperintense on both T1- and T2-weighted images with no contrast enhancement. Histopathological examination revealed monomorphous tumor cells diffusely infiltrating the neuropil with circumferential, radial, or longitudinal angiocentric alignment and subpial aggregation with perpendicular alignment of the cells to the pial surface. Among central nervous system tumors with ependymal differentiation, this distinct entity is the one with an infiltrating growth pattern. In spite of the infiltrating pattern, it does not seem to have a potential for aggressive behavior.

Background: Breast cancer incidence in women increases with age, while survival rates decrease. Studies interpret this result as meaning higher comorbidity, diagnosis at later stages of the disease, and less effective treatment in the elderly. The aim of this study is to evaluate the diagnosis and treatment characteristics of breast cancer and their effect on the survival of women aged 65 and above., Methods: The data within the files of 1064 women with breast cancer, who were followed-up in Dokuz Eylul University Medical Faculty Hospital between 2000 and 2006, were reviewed retrospectively. The survival probabilities at years 1 and 5 were calculated by life table analysis. The Kaplan-Meier test was used for calculating mean survival time, and the differences between groups were evaluated by log-rank test. The backward elimination method was used for multivariate analysis, and a -2 log-likelihood ratio was used for comparison of different models., Results: Of the patients, 25.3% were aged 65 and above at the time of the diagnosis. Patients in this group had more comorbidities and were more likely to be diagnosed at advanced stages than younger patients. Additionally, they had lower rates of surgical treatment, chemotherapy or radiotherapy. One and 5-year survival probabilities among age groups were 96.1% and 84.5%, respectively, for <65 years, 93.5% and 84.8%, respectively, for 65-69, 98.7% and 84.0%, respectively, for 70-74, and 85.5% and 59.6%, respectively, for 75 years and above. In the multivariate model, age, clinical stage, and comorbidity were found to be negatively associated with the survival rate., Conclusions: The survival of women with breast cancer aged 65 and above was affected negatively by age at diagnosis, clinical stage, and the presence of comorbidity. Early diagnosis also is very important for elderly women. Additionally, because of higher comorbidity, their evaluation and treatment should be planned by an interdisciplinary team.

Invasive micropapillary carcinoma (IMPC) of the breast is an uncommon, highly aggressive breast cancer that may occur in pure and mixed forms. Our aim in this study is to investigate the relationship between clinical, histopathologic, and immunohistochemical features of pure and mixed IMPC cases diagnosed and treated at our institution. One hundred and three IMPC cases diagnosed at our institution over a period of 19 years have been selected. Clinical, histopathologic features, as well as hormone status and c-erb-B2 overexpression of tumors were re-evaluated. Mann-Whitney U, chi-squared, Kaplan-Meier, and Fisher's exact tests were used for statistical analyses. Results were considered to be significant at p < 0.05. Twenty cases (19.4%) were pure, and 83 cases (80.6%) were mixed IMPC. The most common nonmicropapillary invasive carcinoma component in mixed cases was invasive ductal carcinoma (IDC; 78.3%). Progesterone receptor was significantly less positive in pure IMPC cases (p = 0.031). There was no statistically significant difference between the two groups, in terms of mean age of the patients (53.0 versus 52.8), mean tumor size (26.6 mm versus 27.7 mm), presence of high-grade tumor (p = 0.631), presence of sentinel lymph node (SN) metastasis (p = 1.000), axillary lymph node metastasis (p = 1.000), lymphatic invasion (p = 1.000) and blood vessel invasion (p = 0.475), c-erbB-2 overexpression of tumor cells (p = 0.616), distant metastasis (p = 0.549), or overall survival (p = 0.759). The local recurrence rate of the two groups was not statistically significant either (16.7% versus 4.3%). However, local recurrence was detected 12% more commonly (p = 0.100), and ~8 months earlier (p = 0.967) in pure IMPC cases, compared to mixed cases. In addition, presence of local recurrence was found to be statistically significantly associated with estrogen receptor (ER) status (p = 0.004), progesterone receptor (PR) status (p = 0.001), and c-erb-B2 overexpression (p = 0.016) in all patients. Overall survival rate was significantly associated with ER staining of the tumor (log-rank = 0.028). Our findings suggest that hormone receptor negativity may explain the more aggressive behavior of pure IMPC compared to mixed cases. Besides, longer survival period of patients with ER positivity, and the relationship of hormone status and c-erb-B2 overexpression and local recurrence further support favorable prognostic value of hormone receptors in invasive breast cancer., (© 2013 Wiley Periodicals, Inc.)

Background: Triple negative (TN) tumor has a relatively high rate of recurrence and distant metastasis, but results of studies revealed that triple positive tumor is an independent predictor of axillary lymph node involvement. Our aim was to evaluate the frequency of nonsentinel lymph node metastasis (NSLNM) involvement in operable TN breast cancer with positive sentinel lymph node (SLN) and predicting the likelihood of NSLNM in this cohort of patients by using 4 different nomograms., Methods: A total of 128 patients with TN and SLN(+) underwent complete axillary lymph node dissection in 14 different centers in Turkey. For comparison, we used our previous multicenter MF08-01 Protocol, which identified 441 patients with estrogen receptor (ER(+)) who had a positive SLN biopsy and underwent subsequent complete axillary lymph node dissection. Turkish, Cambridge, and Stanford nomograms and the Tenon Score system were used to calculate the probability of NSLNM., Results: Patients with TN tumor had a larger tumor size. The actual percentage of NSLN positivity was 41% in the TN group and 47.1% in patient with ER(+). The Tenon Score was ≤3.5 in 12% of patients with TN and ER(+); the area under the curve in the receiver operating characteristics curve were 0.53 and 0.59, respectively. Based on the Turkish, Cambridge, and Stanford nomograms, areas under the curve were 0.54, 0.53, and 0.61, respectively in patients with TN, and were 0.79, 0.72, and 0.70, respectively, in patients with ER(+)., Conclusion: Using the Tenon Score system underestimates NSLN positivity, and tested nomograms are not good discriminators of NSLNM in patients with TN and positive SLN., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: The aim of the study was to evaluate the available breast nomograms (MSKCC, Stanford, Tenon) to predict non-sentinel lymph node metastasis (NSLNM) and to determine variables for NSLNM in SLN positive breast cancer patients in our population., Materials and Methods: We retrospectively reviewed 170 patients who underwent completion axillary lymph node dissection between Jul 2008 and Aug 2010 in our hospital. We validated three nomograms (MSKCC, Stanford, Tenon). The likelihood of having positive NSLNM based on various factors was evaluated by use of univariate analysis. Stepwise multivariate analysis was applied to estimate a predictive model for NSLNM. Four factors were found to contribute significantly to the logistic regression model, allowing design of a new formula to predict non-sentinel lymph node metastasis. The AUCs of the ROCs were used to describe the performance of the diagnostic value of MSKCC, Stanford, Tenon nomograms and our new nomogram., Results: After stepwise multiple logistic regression analysis, multifocality, proportion of positive SLN to total SLN, LVI, SLN extracapsular extention were found to be statistically significant. AUC results were MSKCC: 0.713/Tenon: 0.671/Stanford: 0.534/DEU: 0.814., Conclusions: The MSKCC nomogram proved to be a good discriminator of NSLN metastasis in SLN positive BC patients for our population. Stanford and Tenon nomograms were not as predictive of NSLN metastasis. Our newly created formula was the best prediction tool for discriminate of NSLN metastasis in SLN positive BC patients for our population. We recommend that nomograms be validated before use in specific populations, and more than one validated nomogram may be used together while consulting patients.

Background: The prevalence of thyroid cancer in renal transplant population has not been widely studied, and there is no consensus on the management of thyroid cancer in transplant patients. The aim of this study was to evaluate changes in thyroid hormone levels and investigate the incidence of the thyroid cancer after renal transplantation., Materials and Methods: From October 1989 to April 2007, 122 renal allograft recipients that were being followed underwent thyroid ultrasonography to determine nodules together with thyroid hormone levels. Ultrasound-guided fine-needle aspiration biopsy (FNAB) was performed to the nodules > 10 mm or those with 8-10 mm diameter but with calcifications., Results: One hundred and eight patients (88.5%) had normal thyroid function. None of the patients had overt hypothyroidism, 2 had subclinical hypothyroidism, 10 subclinical thyrotoxicosis, and 2 low T3 syndrome. Mean thyroid volume was 14.2 +/- 7.2 ml. In all, 91.8% was diagnosed with goiter (n = 112). Seventy-two thyroid nodules were detected in 49 kidney allograft recipients (single nodule in 30, multiple in 19 patients). Eighty-four biopsy samples were reported as benign (n = 21, 87.5%), 8 as suspicious (n = 2, 8.3%), and 4 as inadequate (n = 1, 4.1%). After surgery, one of the patients (0.8%) with suspicious FNAB was reported as papillary thyroid carcinoma., Conclusion: Because of the high incidence of thyroid dysfunction in transplant patients, screening of thyroid function should be a part of follow-up. Our results suggest that although frequency of nodules is increased in kidney transplant patients, prevalence of thyroid cancer is slightly, but not significantly, higher than that of the normal population.

We aimed to determine changes in the expression of the genes CDH1, CDH13, CD44, and TIMP3 to look for any relationship between them, HER2 and ESR1 expression at the RNA level, and the histopathological properties of tumors. We also analyzed the expression properties of double-negative (estrogen receptor [ER] and human epidermal growth factor receptor [HER2] both negative) breast tumors. Expression status was studied in fresh tissue at the mRNA level with quantitative PCR using hydrolysis probes. Sixty-two cancer patients and four normal controls were included in the study. When the tumor group was analyzed as a whole, the correlations of ESR1 with CDH1, CDH13, and TIMP3 were P < 0.05, P < 0.005, and P < 0.005, respectively. In ER-positive tumors, CDH1 and CDH13 were correlated directly (P < 0.005) when HER2 was correlated with CDH1, CDH13, and TIMP3 indirectly (P < 0.005, P < 0.005, and P < 0.05, respectively). CDH1 and CD44 had a strong indirect correlation (P < 0.005) in ER-negative tumors. There were significant differences in the expression levels of the CDH13, TIMP3, and CD44 genes (P < 0.005, P < 0.005, and P < 0.05, respectively) between the ER-positive and -negative groups. All four genes were found to be correlated with invasive properties in both ER-positive and -negative tumors. In double-negative tumor samples, only CD44 had a significant and strong correlation with stage, lymph node involvement, and metastasis (P < 0.05, P < 0.005, and P < 0.05, respectively). As a conclusion, a decrease in CDH1, CDH13, and TIMP3 expression levels with an increase in CD44 can be used as an indicator for invasion in both ER-positive and -negative breast tumors. In double-negative tumor tissues, CD44 can be considered a marker for aggressive properties.

The carcinoma frequency of clinically and radiologically negative pathologic nipple discharges (PNDs) and the optimum management strategy of these cases are still unclear. In this study, the frequency of cancer and the situation of the classic surgical intervention in patients with PND and invisible mammographic and ultrasonographic results are reviewed. The data pertaining to the cases of sub-areolar exploration and major duct excision in a surgery clinic of university hospital from December 2002 to June 2007 have been examined in detail. In 28 cases with PND, which did not have any findings during conventional radiologic examinations, 21% of cases had malignant, and 7% of cases had atypical ductal hyperplasia. The frequency of invasive or in situ carcinoma is not low in clinically and radiologically negative PNDs. Sub-areolar exploration and major duct excision seems to be an appropriate and definitive diagnostic and therapeutic option in this special patient group.

Introduction: Peroxisome proliferator-activated receptor gamma (PPAR-gamma) and retinoic acid receptors (RAR/RXR) belong to the nuclear steroid receptor family. In vitro studies have suggested that PPAR-gamma ligands are highly effective in preventing mammary tumours and these effects are enhanced by some retinoids. However, in vivo anti-initiator and anti-promoter efficacies of this combination are not clear., Aim and Methods: The present study aimed to investigate the chemopreventive efficacies of the PPAR-gamma ligand rosiglitazone (200 microg/kg/day), synthetic retinoid fenretinide (0.3 mg/kg/day) and their combination on a DMBA-induced rat mammary carcinogenesis model., Results: In the rosiglitazone group, no malignant tumour developed, apart from the lowest proliferative mammary lesions. In the fenretinide group, 30% developed a malignant tumour but there were no benign tumours. Cancer incidences were 61.5% and 10% in the control and combination groups respectively., Conclusions: Our results showed that the PPAR-gamma ligand rosiglitazone and synthetic retinoid fenretinide have potent chemopreventive properties against in vivo mammary carcinogenesis; however, the efficacies were not enhanced by their combination.

Objective: To evaluate whether endocrinologist-performed ultrasonography improves the localization of parathyroid adenomas in patients with primary hyperparathyroidism., Methods: We performed a retrospective analysis of consecutive patients with primary hyperparathyroidism due to a single adenoma who underwent surgery at the Dokuz Eylul University Hospital in Izmir, Turkey, between January 2000 and January 2008. Data regarding the localization of adenomas were obtained from surgical reports. Neck ultrasonography was performed in all patients as first-line imaging. Parathyroid ultrasonography was performed by a staff radiologist between January 2000 and December 2004. Beginning January 2005, parathyroid ultrasonography was performed blindly by an endocrinologist in addition to the staff radiologist. In the case of discordant preoperative localization between the endocrinologist- and radiologist-performed ultrasonography, surgery was performed according to the technetium Tc 99m sestamibi (MIBI) scan and endocrinologist-performed ultrasonography localization results., Results: A total of 156 patients with primary hyperparathyroidism due to a single adenoma were included. Of the 156 patients, 139 also underwent MIBI scan. Ultrasonography localized 102 parathyroid adenomas (65%). The accuracy of the ultrasonography was improved in patients who underwent endocrinologist-performed ultrasonography. Endocrinologist-performed ultrasonography localized the adenoma correctly in 19 patients for whom the staff radiologist had reported a negative or unsuccessful localization. When ultrasonography results were combined with the MIBI scan findings, parathyroid adenomas were again more likely to be localized in patients who underwent operation after January 2005 and thus had endocrinologist-performed ultrasonography., Conclusion: Our results suggest that endocrinologist-performed ultrasonography improves the preoperative localization of parathyroid adenoma.

Phyllodes tumor (PT) is an uncommon tumor in adolescent girls and young women. A case of PT in a 14-year-old girl is reported. The clinical examination showed a painless tumor that had grown during 10 months. Total excision of the mass with wide margin was performed. The diagnosis, behavior, and treatment of this rare tumor are discussed.

Breast cancer is the most common malignancy in women. However, metastases to the breast from nonmammary malignant neoplasms are rare and were detected at a rate of 0.28% in our series. Clinical and pathologic findings in 5 cases of metastatic tumors (malign mesenchymal tumor, squamous cell carcinoma of the tongue, non-Hodgkin lymphoma, and Sézary syndrome) in the breast are presented and discussed with respect to the literature. Detailed clinical history and a multidisciplinary approach are useful in establishing correct diagnosis and preventing unnecessary radical surgery.

Objective: The aim of this study was to evaluate the changes in follicular development, serum hormonal levels, and endometrium in the pre-implantation period of rats by using recombinant FSH (rFSH) without human chorionic gonadotropin (hCG)., Methods: Thirty female rats were studied in six groups of five specimens. Two groups determined as controls (groups 1 and 2). Two groups received constant doses of rFSH (groups 3 and 4) and other two decreasing doses (groups 5 and 6). One of the paired groups was mated. Uterus, ovaries, and blood samples were taken from non-mated groups (groups 1, 3, and 5) at the proestrus period and from mated groups (groups 2, 4, and 6) in the pre-implantation period., Results: In non-mated groups antral follicles and corpus luteum periodicum and in mated groups antral follicles, corpus luteum periodicum, and corpus luteum graviditatis were increased in rFSH groups, especially in decreasing dose groups. Estradiol (E2) levels were increased and progesterone (P)/E2 ratio was significantly decreased in decreasing dose groups. Endometrium surface epithelium was columnar, irregular, and folded in rFSH groups. Endometrium glandular epithelium was cuboidal in all groups. In decreasing dose groups endometrial stroma was smooth and fibroblastic. Mitotic indices of endometrium surface, glandular epithelium, and stroma were significantly decreased in rFSH groups. Primary follicles and P levels showed no change., Conclusion: It seems likely that decreasing doses of rFSH might be used in order to improve follicular development, although it has negative effects with E2 on endometrium in the pre-implantation period of rats.

This study was undertaken to assess the correlation between the degree of accumulation and the washout of 99m technetium methoxyisobutylisonitrile ((99m)Tc-MIBI) and angiogenesis in MIBI-positive breast lesions. Twenty-eight patients (mean age, 51+/-11 years) with 31 breast lesions who underwent scintimammography were studied. Anterior, left and right prone lateral images were obtained 20 min and 3 h after the injection of 740 MBq (99m)Tc-MIBI. All breast lesions showed increased (99m)Tc-MIBI uptake. Early and delayed tumor to background activity ratios (T/BG) and washout index (early tumor uptake-delayed tumor uptake divided by early tumor uptake) were calculated. Vascular endothelium was immunohistochemically labeled using a biotinylated monoclonal antibody directed against the factor-VIII-associated antigen using standard biotin-avidin technique. Angiogenesis was evaluated by assessing the vascular surface density (VSD) and the microvessel number (NVES) within 10 randomly chosen areas. All pathological data were compared with early and delayed T/BG activity ratios and washout index of (99m)Tc-MIBI. Statistical analysis was performed using Spearman correlation test. There was no statistically significant correlation between the degree of angiogenesis and early T/BG (r = .287, P > .05 with VSD, r = .351, P > .05 with NVES), delayed T/BG (r = .277, P > .05 with VSD, r = .315, P > .05 with NVES) and the washout index (r = .268, P > .05 with VSD, r = .285, P > .05 with NVES) of (99m)Tc-MIBI in all breast lesions. There was no statistically significant correlation between the degree of angiogenesis and early T/BG (r = .235, P > .05 with VSD, r = .356, P > .05 with NVES), delayed T/BG (r = .181, P > .05 with VSD, r = .285, P > .05 with NVES) and the washout index (r = .158, P > .05 with VSD, r = .187, P > .05 with NVES) of (99m)Tc-MIBI in 24 invasive breast lesions. No statistically significant correlation was found between the degree of angiogenesis and early T/BG (r = -.036, P > .05 with VSD, r = -.107, P > .05 with NVES), delayed T/BG (r = -.500, P > .05 with VSD, r = -.429, P > .05 with NVES), but there was a high correlation between angiogenesis and the washout index (r = .893, P < .05 with VSD, r = .964, P < .05 with NVES) of (99m)Tc-MIBI in seven noninvasive breast lesions. Amount of (99m)Tc-MIBI uptake in breast lesions is dependent on several factors. Our study indicates that early and delayed (99m)Tc-MIBI uptakes in MIBI-positive breast lesions are not related to angiogenesis in both invasive and noninvasive breast lesions. But washout index of (99m)Tc-MIBI in noninvasive breast lesions is highly correlated with angiogenesis. (99m)Tc-MIBI scintigraphy does not seem to be able to indicate angiogenic property of invasive breast lesions.

7,12-Dimethylbenz[a]anthracene (DMBA), a polycyclic aromatic hydrocarbon (PAH), has been used extensively as a tool to initiate mammary carcinogenesis and subsequent chemoprevention. On the other hand, selenium (Se) is potentially useful in oncology because this element possesses anticarcinogenic and chemopreventive properties. Se-containing enzymes such as glutathione peroxidase (GPx) play an important role in PAH metabolism and detoxification. In this study, rats were administered a single, oral dose of DMBA (12 mg). In the Se group, rats received 20 microg Se daily via gavage, starting 2 wk before the DMBA administration and continued for 1 wk. One hundred twenty days after DMBA administration the rats were sacrificed and toxicity was evaluated using histopathological and biochemical criteria. Five rats (30%) died in the DMBA group within the study period, whereas no death occurred in the DMBA-Se-treated group. Malignant tumor frequency was 33% in the DMBA group, while no malignant tumors occurred in the DMBA-Se-treated group. Some inflammatory changes rather than epithelial changes were found upon histopathological examination. GPx activity and blood urea nitrogen levels were higher and kidney GST activity was lower in the DMBA-Se-treated group compared to DMBA alone. In conclusion, Se appears to be effective in preventing some of the adverse effects associated with DMBA.

A 62-year-old woman being treated for stage IIIC rectal adenocarcinoma was diagnosed with primary non-Hodgkin lymphoma of the breast after a 4-year follow-up. This case illustrates the importance of close and long-term follow-up as well as of differential diagnostic procedures for second primary malignancies after the initial diagnosis and treatment of a solid tumor.

The purpose of this study was to use comparative genomic hybridization (CGH) to screen breast tumors for copy number changes: 22 ductal, 9 lobular, 7 mixed, 2 micropapillary carcinomas, and 2 ductal carcinoma in situ were studied and various regional genomic imbalances were detected. The majority of the aberrations identified in this study were in line with previous CGH findings. The most frequent DNA sequence copy number changes were 1q, 8q, and 20q gains. The frequency of 16q losses was significantly higher in lobular carcinomas. The nodal involvement was 10 times higher in cases showing losses of 13q than in cases having normal peak profile at this region. Estrogen receptor positivity was significantly higher in cases displaying 20q gains and 16q losses. Unambiguous high-level DNA amplifications have also been detected. These mapped to 4q31, 6q21 approximately q22, 8q21 approximately q24, 8p11.2 approximately p12, 11q13, 15q24 approximately qter, 20q13.1 approximately qter, and 20q12 approximately qter chromosomal locations. Our results highlight several chromosomal regions that may be important in the molecular genetics of distinct clinicopathologic breast cancer subgroups.

Microsatellite instability (MSI) is a form of genomic instability associated with defective DNA mismatch repair in tumors. MSI is found in 85-90% of hereditary nonpolyposis colorectal cancer cases; however, its occurrence in breast carcinogenesis still remains to be clarified. In addition, data are limited on the incidence of MSI in the medullary subtype. The purpose of this study was to investigate the occurrence of MSI in medullary breast cancer (MBC). The study included a total of 16 patients with MBC, nine with typical and seven with atypical histology. The incidence of MSI in five microsatellite loci (D2S123, D3S1611, D17S807, D17S796 and Xq11-12) was determined by comparing paired normal and tumor tissue DNA after PCR amplification from paraffin-embedded tissues. All 16 tumors showed stability at five loci. Although the number of microsatellite markers and DNA samples may limit the value of our results, we conclude that the MSI phenotype is uncommon in human MBC.

Breast cancer in a young person is considered a rare and very aggressive disease. The theories addressing the underlying genetic mechanisms of this disease are controversial. Therefore, additional genetic concepts playing a possible role in its pathogenesis and prognosis must be investigated. Microsatellite instability (MSI) characterized by a mutational process of insertions or deletions in microsatellite repeats might constitute a sensitive indicator for genomic instability in cancer. MSI has been described in a wide variety of tumors, particularly in hereditary non-polyposis colorectal cancer. The reports regarding its occurrence and prognostic significance in breast cancer are in conflict with each other. The purpose of this study was to investigate MSI in early-onset breast cancer and to correlate its occurrence with clinicopathological prognisticators. In this study, 16 female patients with primary breast cancer under 35 years of age (range 29-34) were investigated for the incidence of MSI in five microsatellite loci (D2S123, D3S1611, D17S807, D17S796 and Xq11-12) by comparing paired normal and tumor tissue DNA after PCR amplification from paraffin-embedded tissues. No instability was found in any of these five microsatellite loci. Although care must be taken not to overstate the importance of this result due to the inadequate number of microsatellite markers and DNA samples studied, this preliminary report indicates that MSI phenotype is uncommon in human early-onset breast cancer. Therefore, it does not appear to be related to the prognosis of disease.