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Fanconi anemia (FA) is a heritable malformation, bone marrow failure and cancer predisposition syndrome that confers an exceptionally high risk of developing carcinomas arising in squamous mucosal epithelia lining the mouth, proximal esophagus, vulva and anus. The origin of these cancers is not understood, and no effective way has been identified to prevent or delay their appearance. FA-associated carcinomas are also therapeutically challenging, as they may be multi-focal and stage-advanced at diagnosis making surgical control challenging. Moreover, individuals with FA have systemic DNA damage hypersensitivity and thus an elevated risk of toxicity when treated with standard-of-care therapies such as DNA cross-linking drugs and ionizing radiation.We developed the Fanconi Anemia Cancer Cell Line Resource (FA-CCLR) in order to foster new research on the origins, treatment, and prevention of FA-associated cancers. The FA-CCLR consists of FANC-isogenic head and neck squamous cell carcinoma (HNSCC) cell line pairs from cancers arising in individuals with FA, or newly engineered from sporadic HNSCC cell lines. Molecular, cellular, and biochemical analyses were used to demonstrate the causal dependence of key FA-associated phenotypes on FANC genotype, expression and pathway activity. These FANC-isogenic cell line pairs are available to academic and non-profit investigators, with ordering information available at the ‘Fanconi Anemia Research Materials’ Resource and Repository at Oregon Health & Sciences University, Portland OR.SignificanceWe have generated new isogenic cancer cell line models to investigate the origins, treatment and prevention of Fanconi anemia-associated squamous carcinomas that target the oral mucosa, proximal esophagus, and anogenital region.

Prior models have been developed to predict survival for patients with esophagogastric cancer undergoing curative treatment or first-line chemotherapy (SOURCE models). Comprehensive clinical prediction models for patients with esophagogastric cancer who will receive second-line chemotherapy or best supportive care are currently lacking. The aim of our study was to develop and internally validate a new clinical prediction model, called SOURCE beyond first-line, for survival of patients with metastatic esophagogastric adenocarcinoma after failure of first-line palliative systemic therapy. Patients with unresectable or metastatic esophageal or gastric adenocarcinoma (2015-2017) who received first-line systemic therapy (N = 1067) were selected from the Netherlands Cancer Registry. Patient, tumor and treatment characteristics at primary diagnosis and at progression of disease were used to develop the model. A Cox proportional hazards regression model was developed through forward and backward selection using Akaike's Information Criterion. The model was internally validated through 10-fold cross-validations to assess performance. Model discrimination (C-index) and calibration (slope and intercept) were used to evaluate performance of the complete and cross-validated models. The final model consisted of 11 patient tumor and treatment characteristics. The C-index was 0.75 (0.73-0.78), calibration slope 1.01 (1.00-1.01) and calibration intercept 0.01 (0.01-0.02). Internal cross-validation of the model showed that the model performed adequately on unseen data: C-index was 0.79 (0.77-0.82), calibration slope 0.93 (0.85-1.01) and calibration intercept 0.02 (-0.01 to 0.06). The SOURCE beyond first-line model predicted survival with fair discriminatory ability and good calibration.

The VEGF-A monoclonal antibody bevacizumab is currently recommended for first-line treatment of all metastatic colorectal cancer (mCRC) patients. Cost-benefit ratio and side-effects however necessitate patient selection. A large retrospective yet nonrandomized study showed that patients with loss of chromosome 18q11.2-q12.1 in the tumor and treated with bevacizumab have 3 months improved median progression-free (PFS) and overall survival (OS) benefit compared to patients without this loss and/or treatment modality. Implementation for loss of chromosome 18q11.2-q12.1 as a marker in clinical practice mandates evidence in a randomized controlled trial for bevacizumab. Of the trials with randomization of chemotherapy vs chemotherapy with bevacizumab, the AGITG-MAX trial was the only one with tumor materials available. Chromosome 18q11.2-q12.1 copy number status was measured for 256 AGITG-MAX trial patients and correlated with PFS according to a predefined analysis plan with marker-treatment interaction as the primary end-point. Chromosome 18q11.2-q12.1 losses were detected in 71% of patients (181/256) characteristic for mCRC. Consistent with the nonrandomized study, significant PFS benefit of bevacizumab was observed in patients with chromosome 18q11.2-q12.1 loss (P =.009), and not in patients without 18q loss (P =.67). Although significance for marker-treatment interaction was not reached (Pinteraction =.28), hazard ratio and 95% confidence interval of this randomized cohort (HRinteraction = 0.72; 95% CI = 0.39-1.32) shows striking overlap with the nonrandomized study cohorts (HRinteraction = 0.41; 95% CI = 0.32-0.8) supported by a nonsignificant Cochrane χ2 test (P =.11) for heterogeneity. We conclude that post hoc analysis of the AGITG-MAX RCT provides supportive evidence for chromosome 18q11.2-q12.1 as a predictive marker for bevacizumab in mCRC patients.

Pancreatic cancer (PC) survival is poor, as detection usually occurs late, when treatment options are limited. Screening of high‐risk individuals may enable early detection and a more favorable prognosis. Knowledge gaps prohibit establishing the effectiveness of screening. We developed a Microsimulation Screening Analysis model to analyze the impact of relevant uncertainties on the effect of PC screening in high‐risk individuals. The model simulates two base cases: one in which lesions always progress to PC and one in which indolent and faster progressive lesions coexist. For each base case, the effect of annual and 5‐yearly screening with endoscopic ultrasonography/magnetic resonance imaging was evaluated. The impact of variance in PC risk, screening test characteristics and surgery‐related mortality was evaluated using sensitivity analyses. Screening resulted in a reduction of PC mortality by at least 16% in all simulated scenarios. This reduction depended strongly on the natural disease course (annual screening: −57% for “Progressive‐only” vs −41% for “Indolent Included”). The number of screen and surveillance tests needed to prevent one cancer death was impacted most by PC risk. A 10% increase in test sensitivity reduced mortality by 1.9% at most. Test specificity is important for the number of surveillance tests. In conclusion, screening reduces PC mortality in all modeled scenarios. The natural disease course and PC risk strongly determines the effectiveness of screening. Test sensitivity seems of lesser influence than specificity. Future research should gain more insight in PC pathobiology to establish the true value of PC screening in high‐risk individuals., What's new? About 10 percent of pancreatic cancers occur in individuals with inherited risk factors. While screening such high‐risk individuals can facilitate the detection of precursor lesions and early‐stage cancer, the extent to which benefits outweigh harms, including overdiagnosis, remains unknown. Here, using a microsimulation model, the authors explored uncertainties concerning the early detection of pancreatic cancer and analyzed the impact of these uncertainties on the effect of screening. In all simulated scenarios, screening was associated with reduced pancreatic cancer mortality. The effectiveness of screening was most strongly impacted by characteristics of natural disease course and level of pancreatic cancer risk

High‐grade cervical intraepithelial neoplasia (CIN2 and CIN3) represents a heterogeneous disease with varying cancer progression risks. Biomarkers indicative for a productive human papillomavirus (HPV) infection (HPV E4) and a transforming HPV infection (p16ink4a, Ki‐67 and host‐cell DNA methylation) could provide guidance for clinical management in women with high‐grade CIN. This study evaluates the cumulative score of immunohistochemical expression of p16ink4a (Scores 0‐3) and Ki‐67 (Scores 0‐3), referred to as the “immunoscore” (IS), in 262 CIN2 and 235 CIN3 lesions derived from five European cohorts in relation to immunohistochemical HPV E4 expression and FAM19A4/miR124‐2 methylation in the corresponding cervical scrape. The immunoscore classification resulted in 30 lesions within IS group 0‐2 (6.0%), 151 lesions within IS group 3‐4 (30.4%) and 316 lesions within IS group 5‐6 (63.6%). E4 expression decreased significantly from CIN2 to CIN3 (P, What's new? Treating all high‐grade cervical intraepithelial neoplasia (CIN2/3) with excisional therapy leads to overtreatment, as these lesions have varying cancer progression risks. Here, the authors evaluated expression patterns of p16ink4a, Ki‐67 and the HPV E4 protein, and methylation of FAM19A4/miR124‐2 in high‐grade CIN. The biomarker expression patterns revealed the high degree of heterogeneity among CIN2/3 lesions. Biomarker profiles based on the presumed cancer progression risks were established and could guide clinicians in choosing whether to treat immediately or wait and see.

In human papillomavirus (HPV) cervical cancer screening, cytology is used as triage to counter the low specificity of HPV testing. VALID‐SCREEN is a EU‐multicenter, retrospective study conducted to evaluate the clinical performance of the FAM19A4/miR124‐2 methylation‐based molecular triage test as a substitute or addition to cytology as reflex testing of HPV screen positive women. FAM19A4/miR124‐2 methylation test (QIAsure Methylation Test) was evaluated in 2384 HPV‐positive cervical screening samples, from women 29‐76 years of age, derived from four EU countries. Specimens were collected in ThinPrep or SurePath media, HPV‐status, concurrent cytology, and histology diagnosis were provided by the parent institutes. The control population consisted of women with no evidence of disease within 2 years of follow‐up. A total of 899 histologies were retrieved; 527 showed no disease, 124 CIN2 (5.2%), 228 CIN3 (9.6%) and 20 cervical cancers (0.8%); 19 of 20 screen‐detected cervical cancers were found methylation‐positive (sensitivity 95%). Overall specificity of FAM19A4/miR124‐2 methylation test was 78.3% (n = 2013; 95%CI: 76‐80). The negative predictive value of hrHPV positive, methylation‐negative outcomes were 99.9% for cervical cancer (N = 1694; 95%CI: 99.6‐99.99), 96.9% for ≥CIN3 (95%CI: 96‐98), and 93.0% for ≥CIN2 (95%CI: 92‐94). Overall sensitivity for CIN3 using FAM19A4/miR124‐2 methylation test was 77% (n = 228; 95%CI: 71‐82). CIN3 sensitivity was uniform between centers independent of sample collection medias, DNA extraction methods and HPV screening tests. Being objectively reported compared to the subjectivity of cytology, equally performing across settings and screening methods, the FAM19A4/miR124‐2 methylation constitute an alternative/supplement to cytology as triage method to be investigated in real‐life pilot implementation., What's new? In HPV screening for cervical cancer, cytology has been used to triage those women who are hrHPV‐positive. However, cytology is subjective, and skilled cytologists are often in short supply. A molecular test using specific biomarkers might offer better results. In this large European study, the authors found that a new standardized test for the methylation biomarker combination FAM19A4/miR124‐2 did indeed yield results that were equal to or better than triage by cytology, in determining which hrHPV‐positive women should be referred for colposcopy.

Birth cohorts vaccinated against human papillomavirus (HPV) are now entering cervical cancer screening. Assessment of (pre)cancer (CIN3+) risk is needed to assess the residual screening need in vaccinated women. We estimated the lifetime (screen‐detected) CIN3+ risk under five‐yearly primary HPV screening between age 30 and 60, using HPV genotyping and histology data of 21,287 women participating in a screening trial with two HPV‐based screening rounds, 5 years apart. The maximum follow‐up after an HPV‐positive test was 9 years. We re‐estimated the CIN3+ risk after projecting direct vaccine efficacy for the bivalent and the nonavalent HPV vaccines, assuming life‐long protection. The lifetime CIN3+ risk was 4.1% (95% confidence interval 3.5‐4.9) and declined by 53.5% and 70.5% after bivalent vaccination without and with cross‐protection, respectively, translating into a residual lifetime CIN3+ risk of 1.9% (1.4‐2.4) and 1.2% (0.9‐1.5). The CIN3+ risk declined by 88.5% after nonavalent vaccination, translating into a residual lifetime CIN3+ risk of 0.5% (0.2‐0.7). The latter risk increased to 1.6% when vaccine protection only lasted until the first screening round at age 30. Among HPV‐positive women with abnormal adjunct cytology, the nine‐year CIN3+ risk was 16.9% (8.7‐32.4) after nonavalent vaccination. In conclusion, HPV vaccination will lead to a strong decline in the lifetime CIN3+ risk and the remaining absolute CIN3+ risk will be very low. Primary HPV testing combined with adjunct cytology at five‐year intervals still seems feasible even after nonavalent vaccination, although unlikely to be cost‐effective. Our results support a de‐intensification of screening programs in settings with high vaccination coverage., What's new? Human papillomavirus (HPV)‐based screening and vaccination are key strategies for early detection and prevention of cervical intraepithelial neoplasia grade 3 and cancer (CIN3+). Here the authors estimated the lifetime screen‐detected CIN3+ risk expected under different HPV vaccination scenarios using a novel statistical, data‐driven approach that deals with multiple‐type HPV infections. The model estimated that the lifetime CIN3+ risks under five‐yearly primary HPV screening will become very low in vaccinated women, in particular when protection is life‐long and provided beyond genotypes 16 and 18. These CIN3+ risks are important when defining new extended screening intervals for vaccinated cohorts.

The risk of vulvar squamous cell carcinoma (VSCC) in patients with high‐grade vulvar intraepithelial neoplasia (VIN) is considered lower in high‐grade squamous intraepithelial lesion (HSIL) compared to differentiated VIN (dVIN), but studies are limited. Our study investigated both the incidence of high‐grade VIN and the cumulative incidence of VSCC in patients with HSIL and dVIN separately. A database of women diagnosed with high‐grade VIN between 1991 and 2011 was constructed with data from the Dutch Pathology Registry (PALGA). The European standardized incidence rate (ESR) and VSCC risk were calculated, stratified for HSIL and dVIN. The effects of type of VIN (HSIL vs dVIN), age and lichen sclerosis (LS) were estimated by Cox regression. In total, 1148 patients were diagnosed with high‐grade VIN between 1991 and 2011. Between 1991‐1995 and 2006‐2011, the ESR of HSIL increased from 2.39 (per 100 000 woman‐years) to 3.26 and the ESR of dVIN increased from 0.02 to 0.08. The 10‐year cumulative VSCC risk was 10.3%; 9.7% for HSIL and 50.0% for dVIN (log rank P, What's new? High‐grade squamous intraepithelial lesions (HSILs) and differentiated vulvar intraepithelial neoplasia (dVIN) are established risk factors for vulvar squamous cell carcinoma. Lesions classified as dVIN are less common than HSILs but potentially more aggressive. Our study, based on investigation of more than 1100 patients diagnosed with high‐grade VIN between 1991 and 2011, demonstrates a rising incidence of both HSIL and dVIN. Ten‐year cumulative risk of vulvar cancer was significantly greater for dVIN than HSIL. The findings highlight the importance of timely identification and classification of dVIN precancerous lesions and a potential need for risk stratification to prevent overtreatment in HSIL patients.

Circulating tumor DNA (ctDNA) is assumed to reflect tumor burden and has been suggested as a tool for prognostication and follow‐up in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC). However, the prognostic value of ctDNA and its relation with tumor burden has yet to be substantiated, especially in mPDAC. In this retrospective analysis of prospectively collected samples, cell‐free DNA from plasma samples of 58 treatment‐naive mPDAC patients was isolated and sequenced using a custom‐made pancreatobiliary NGS panel. Pathogenic mutations were detected in 26/58 (44.8%) samples. Cross‐check with droplet digital PCR showed good agreement in Bland–Altman analysis (p = 0.217, nonsignificance indicating good agreement). In patients with liver metastases, ctDNA was more frequently detected (24/37, p, What's new? Circulating tumor DNA (ctDNA) attracts much interest as a possible prognostic tool for cancer. Here, the authors showed that the quantity of ctDNA correlated strongly with tumor volume in metastatic pancreatic ductal adenocarcinoma (mPDAC). They conducted a retrospective analysis using samples collected from 58 untreated mPDAC patients. For this study, the authors designed a pancreatobiliary NGS panel, which they used to test the patients’ cell‐free DNA, along with droplet digital PCR. Both ctDNA variant allele frequency and tumor volume predicted overall survival, they found.

Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive tumor with a five-year survival of less than 6%. Chronic pancreatitis (CP), an inflammatory process in of the pancreas, is a strong risk factor for PDAC. Several genetic polymorphisms have been discovered as susceptibility loci for both CP and PDAC. Since CP and PDAC share consistent number of epidemiologic risk factors, the aim of this study was to investigate whether specific CP risk loci also contribute to PDAC susceptibility. We selected five common SNPs (rs11988997, rs379742, rs10273639 rs2995271 and rs12688220) that were identified as susceptibility markers for CP and analyzed them in 2,914 PDAC cases, 356 CP cases and 5,596 controls retrospectively collected in the context of the international PANDoRA consortium. We found a weak association between the minor allele of the PRSS1-PRSS2-rs10273639 and an increased risk of developing PDAC (ORhomozygous =1.19, 95% CI 1.02-1.38, p=0.023). Additionally all the SNPs confirmed statistically significant associations with risk of developing CP, the strongest being PRSS1-PRSS2-rs10273639 (ORheterozygous =0.51, 95% CI 0.39-0.67, p=1.10x10(-6) ) and MORC4-rs 12837024 (ORhomozygous =2.07 (1.55-2.77, ptrend =0.7x10(-11) ). Taken together, the results from our study do not support variants rs11988997, rs379742, rs10273639 rs2995271 and rs12688220 as strong predictors of PDAC risk, but further support the role of these SNPs in CP susceptibility. Our study suggests that CP and PDAC probably do not share genetic susceptibility, at least in terms of high frequency variants. This article is protected by copyright. All rights reserved.

The E48 antigen is a successfully explored molecular marker for the diagnosis and therapy of HNSCC. The applicability of E48 as an HNSCC-associated antigen, however, is restricted due to its heterogeneous expression in 30% of tumors; and identification of additional target antigens is therefore desired. E48 belongs to the Ly-6 antigen family, comprising a group of highly homologous, low m.w., GPI-anchored surface proteins, of which some show tissue-restricted expression patterns. To identify novel human HNSCC-associated Ly-6 members with squamous cell-associated expression patterns, we performed comprehensive gene-screening consisting of BLAST searches within Gen-Bank databases, followed by expression analysis. Using this approach, the Ly-6K gene could be annotated as a novel member of the human Ly-6 family. Expression of the human Ly-6 genes E48, Ly-6K, PSCA, GML, RIG-E, G6C and Ly-6H was prescreened by qualitative RT-PCR and subsequently analyzed by quantitative RT-PCR in normal keratinocytes, HNSCC cell lines, normal mucosa, HNSCC tumors as well as normal peripheral blood and bone marrow cells. PSCA was highly expressed in normal mucosa, but 100-fold decreased expression was seen in HNSCC. For Ly-6H, GML and G6C, no or very low expression was observed in keratinocytes and HNSCC. Expression of RIG-E was high in normal and malignant squamous cells and in peripheral blood and bone marrow cells, thus limiting its applicability as an HNSCC-associated marker. In contrast, besides the E48 gene, the Ly-6K gene also appeared to be selectively expressed in HNSCC and normal squamous cells. Moreover, expression of Ly-6K was shown in HNSCC cell lines, in which no E48 expression could be detected. These data justify further evaluation of Ly-6K as potential target antigen for the diagnosis and therapy of HNSCC.

Retinoids, analogues of vitamin A, can reverse premalignant lesions and prevent second primary tumors in patients with head and neck squamous cell carcinoma (HNSCC). The effects of retinoids are mediated by retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which act as ligand-activated transcription factors. The regulation of cell growth, differentiation and retinoid metabolism in normal, premalignant and malignant cells by retinoids is thought to be a result of their effects on gene expression. We investigated mRNA expression of RARs (alpha, beta, and gamma) and RXR-beta by means of RNase protection and related this to retinoic acid (RA)-induced growth inhibition and RA turnover in four HNSCC cell lines (UM-SCC-14C, UM-SCC-22A, UM-SCC-35 and VU-SCC-OE). An RA-resistant subline of UM-SCC-35 was generated by exposure to increasing concentrations of RA for 8 months (designated UM-SCC-35R). RA turnover was determined on the basis of decreasing RA levels in the cells and culture medium after exposure to 1 microM RA. We found that RAR-gamma mRNA expression was strongly correlated with RA-induced growth inhibition (p = 0.016, R = 0.92) and RA turnover (p = 0.041, R = 0.86). RAR-beta transcript levels were reduced in three of five cell lines compared with normal mucosa, and these did not correlate with RA-induced growth inhibition and RA turnover. Expression of RAR-alpha and RXR-beta was not substantially altered in any of the cell lines. These findings suggest that in HNSCC cell lines RAR-gamma is the most important retinoid receptor for regulation of RA turnover rate and RA-induced growth inhibition.

Infection with oncogenic human papillomavirus (HPV) types is associated with the development of cervical neoplasia (CIN). The E6 and E7 oncoproteins are constitutively expressed in these lesions and are therefore putative targets for the immune response against HPV. The relation between HPV 16-specific memory cytotoxic T-cell precursor (mCTLp) activity to both oncoproteins and the natural course of cervical dysplasia was analyzed in 38 patients participating in a nonintervention cohort study of women with CIN and II HPV 16-positive cervical carcinoma patients. In a cross-sectional study at the end of follow-up prior to biopsy, 8 of 20 patients with a persistent HPV 16 infection had specific mCTLp against at least one of the two oncoproteins. By contrast, no specific mCTLp activity was detected in II HPV-negative patients or in 7 patients who had cleared an HPV 16 infection at the end of follow-up. However, 5 of II cervical carcinoma patients showed mCTLp activity against the E7 protein only. This study demonstrates that HPV 16 oncogene-specific mCTLp are present in women with HPV 16-positive CIN prior to any intervention. Since HPV-specific mCTLp were detected predominantly in women with high-grade lesions or invasive cervical carcinoma and not in women who cleared the virus, the role of naturally occurring mCTLp in the protection against HPV-associated cervical neoplasia remains to be established. (C) 2000 Wiley-Liss, Inc.

CD44 splice variants, especially those containing the v6 domain, are assumed to play a critical role in the malignant progression of many human tumors. This concept was based on (i) the aberrant expression of CD44v6 in malignant cells, often encoded by alternatively spliced transcripts, and (ii) the absence of CD44v6 expression in corresponding normal tissues. Remarkably, data on CD44v6 expression in squamous cells do not support this hypothesis: the v6 domain is highly expressed in normal squamous tissues and down- regulation has been described in the majority of squamous-cell carcinomas of the head and neck (HNSCC). In this study, we have compared the expression of v6 in normal oral mucosa and HNSCC in a qualitative and quantitative way. Immunohistochemistry was performed with 3 different anti-v6 antibodies (U36, U39 and VFFI8) on a large panel of HNSCC cell lines and tumors. The v6- encoding splice variants were characterized by screening a cDNA library of a human HNSCC cell line and by RT-PCR on HNSCC cell lines, microdissected normal mucosa and primary as well as metastatic HNSCC tissue. The results revealed that there is no, or only marginal, down-regulation of CD44v6 in HNSCC. About 97% of the primary HNSCC tumors exhibited a high and homogeneous staining pattern (U36, 270/277; U39, 268/277 tumors with more than 50% positive cells). Furthermore, the v6-containing CD44 splice variants present in HNSCC primary tumors and metastases were identical to those expressed in normal mucosa. Our data indicate that v6-containing CD44 splice variants do not play a role in the malignant progression of HNSCC.

Rhenium-186 based radioimmunotherapy (RIT) may have potential for the treatment of minimal residual disease in patients with squamous cell carcinoma of head and neck (HNSCC). In an effort to enhance the efficacy of RIT, we evaluated the combination of RIT and anti-epidermal growth factor receptor (EGFR) therapy in nude mice bearing established HNSCC s.c. xenografts. For this purpose we used the EGFR-blocking monoclonal antibody (MAb) 425. Treatment of HNSCC-bearing mice with the combination of a single administration of 200 μCi 186Re-labeled MAb U36 as well as 1.1 mg unlabeled MAb 425 showed an enhanced efficacy in comparison to the single treatments. When 500 μCi 186Re-labeled MAb U36 were administered, all tumors eventually regressed completely. The combination of this RIT treatment with multiple injections of MAb 425 significantly increased the rate of tumor regression. Although RIT with 186Re-labeled MAbs appears to be very efficient on HNSCC xenografts, the combination with anti-EGFR MAb 425 may enhance the efficacy. Int. J. Cancer 77:13–18, 1998.© 1998 Wiley-Liss, Inc.

At present, tumor-targeting with monoclonal antibodies (MAbs) is among the most promising novel adjuvant-therapy modalities for the treatment of patients with minimal residual disease of head-and-neck squamous-cell carcinoma (HNSCC). For this purpose we developed MAb U36, recognizing a 200-kDa antigen expressed on the outer cell surface of squamous-cell carcinomas and their normal counterparts. Clinical radioimmunoscintigraphy (RIS) and biodistribution studies have shown that the MAb-U36-defined antigen is a suitable target molecule for antibody-based therapy of head-and-neck cancer. In the present study we further characterized the antigen by cDNA cloning. The cDNA was isolated by expression cloning in COS-7 cells. Sequence analysis and database searching revealed that the MAb-U36-defined antigen is identical to the squamous-cell-specific CD44 splice variant epican. The epitope recognized by MAb U36 was mapped by screening overlapping synthetic peptides of the epican-specific region encoded by exon 7-11 (v3-v7), and appeared to be located in the v6 domain. The applicability of MAb U36 for targeting human tumors of various origin expressing the CD44vb domain is discussed.

IgG reactivity against the immunodominant region aa6-35 of Human Papillomavirus (HPV) type-16 E7 was determined in a peptide-based ELISA in a cohort study of women with initial mild to moderate cervical dyskaryosis. On the basis of HPV DNA patterns, as determined by PCR in cervical smears prior to IgG testing, HPV-16-positive patients were grouped as having either a cleared, a fluctuating, or a persistent HPV-16 infection. In a cross-sectional study at the start of serological follow-up, positive IgG reactivities were found more often in the total group of HPV-16-positive patients (20.0%) than in patients consistently typed as HPV-negative over a period of at least 12 months prior to testing (3.1%, p < 0.04). The highest proportion of positive responders was found in patients with a cleared HPV-16 infection (29.4%). Also, IgG reactivities found in HPV-16 clearance patients were significantly higher than in patients with a persistent infection (p < 0.008). In a subsequent longitudinal study over a period of up to 27 months, consistently positive reactivities were observed in patients with cleared viral infections who showed seroreactivity in the cross-sectional study, while mostly negative reactivities were found in patients with viral persistence. HPV-16 E7-specific IgG subclass responses were determined in a selection of 19 CIN and 11 HPV-16-positive cervical carcinoma (CeCa) patients with positive E7-specific IgG responses. IgG2 was predominant in the CIN patients, suggesting the presence of IFNgamma (Th1) at the site of HPV infection. In the CeCa patients IgG1 and IgG2 were produced equally, possibly indicating a rise in Th2 cytokines. Our data suggest that HPV-16 E7 IgG reactivity in a subset of CIN patients with viral clearance may result from successful Th1 responses.

It has been reported that an intrinsic susceptibility to cancer is related to the way an individual responds to DNA-damaging agents. The aim of this study was to evaluate whether, in addition to bleomycin-induced chromosomal instability, radiation-induced initial DNA damage and subsequent repair is associated with the development of head-and-neck squamous-cell carcinoma. In this study, 2 assays were performed to measure DNA damage in human peripheral-blood lymphocytes. One was a chromosomal aberration assay which determines sensitivity to chromatid breaks induced by bleomycin, the other an elegant immunochemical assay which measures the level of radiation-induced strand breaks as well as subsequent repair. Age, smoking and alcohol-drinking behavior did not influence the number of chromatid breaks, initial DNA damage or repair capacity. As has been found in previous studies, the mean number of chromatid breaks per cell was significantly different between patients (n = 18) and control persons (n = 19), whereas the amount of initial DNA damage was not. No correlation was found between the outcome of the 2 assays in the subject groups. In contrast to laryngeal-carcinoma patients, oral-cavity-carcinoma patients showed significantly slower repair capacity than controls. Our hypothesis is that the way DNA damage is processed by the patients determines at which site cancer develops in the head and neck area.

Using viable cells of a human squamous‐cell carcinoma (SCC) cell line as immunogen, we generated 2 monoclonal antibodies, MAbs K984 and K928, to SCC surface antigens. Immunoperoxidase staining of frozen sections of normal epidermis revealed that MAb K984 reacts with the poorly differentiated basal cells, while MAb K928 is reactive with the more highly differentiated suprabasal cells. A similar complementary reaction pattern of these antibodies was demonstrated in the majority of well‐differentiated human tumors and some moderately differentiated SCCs. In contrast, simultaneous reactivity of MAb K984 and K928 was found for the majority of cells within other well‐and moderately differentiated SCCs, as well as all poorly differentiated SCCs. Further biochemical characterization indicated that the antigen recognized by MAb K984 is similar to the one recognized by MAb SF‐25. MAb K928 recognizes a 50‐to 55‐kDa molecule under non‐reducing conditions. Antibodies with similar features to MAb K928 have not been described previously. The antigens recognized by MAbs K984 and K928 can be regarded as novel markers associated with cellular maturation in squamous epithelia. The antigen detected by MAb K984 is probably associated with the proliferating fraction in SCCs.

Monoclonal antibody (MAb) K 112 was generated after a single intrasplenic immunization with a recurrent laryngeal squamous‐cell carcinoma. The antibody detects a 43‐kDa nuclear antigen, with a pl of 5.4, which is expressed only in cycling cells. Expression is typically seen in a granular pattern excluding the nucleoli. During mitosis the bulk of the antigen is diffusely distributed in the cytoplasm. Identical reactivity was observed for tissues or cells of all mammalian species tested. These data indicate that MAb K 112 recognizes a protein belonging to the class of cell‐cycle‐related nuclear antigen molecules.

Human papillomavirus (HPV) is a necessary factor in the pathogenesis of cervical cancer. Circulating HPV-speciflc T-cells responding to the E6 and E7 HPV proteins can be detected only in half of cervical cancer patients. Potential explanations for the absence of this response are lack of sufficient amounts of antigen to activate the immune response or local immune escape mechanisms. We studied the relationship between HPV 16 E6/E7 oncogene mRNA expression, human leukocyte antigen (HLA) expression on tumor cells and the presence of circulating E6- and E7-speciflc T-cell responses in cervical cancer patients. The amount of antigen was assessed by HPV E6/E7 mRNA expression levels measured by quantitative polymerase chain reaction. HLA Class I and Class II expression on tumor cells was analyzed by immunohistochemistry. A proliferative HPV-speciflc T-cell response was detected in 15/29 patients. The amount of HPV E6/E7 mRNA was not related to the presence of immune response. HLA Class I expression was downregulated in 19 patients and completely lost in 7 patients. HLA Class II expression was upregulated in 18 patients. HLA Class I expression on tumor cells showed a strong correlation with immunity (p = 0.001). Explicitly, all patients with complete HLA loss lacked HPV specific T-cell responses. The presence of circulating HPV-specific T-cells might reflect ongoing antitumor response that is sustained by CD8+ T-cells killing HLA Class I positive cancer cells. We hypothesize that HLA Class I expression status on tumor cells might as well influence the response to HPV E6/E7 directed immunotherapy.

In patients with cancer, antibody‐dependent cellular cytotoxicity (ADCC) may be used as a laboratory test or for enhancing immunotherapy with murine monoclonal or chimeric mouse/human anti‐tumor antibodies (mMAbs or cMAbs, respectively). We have established an ADCC assay with IgG1 cMAb SF‐25, using human squamous‐cell carcinoma of the head and neck (SCCHN) cell lines as targets. By flow cytometry, all SCCHN cell lines tested expressed the antigen recognized by cMAb SF‐25. Trypsinization of the cell monolayers facilitated binding of cMAb SF‐25 to the antigen on the cell surface of SCCHN targets. Using the PCI‐50 SCCHN cell line as a target coated with this cMAb at the optimal concentration of 1.0 μg/ml, normal human peripheral blood mononuclear cells (PBMC, n = 28) were found to mediate ADCC at a mean level of 283 ± 42 (SEM) lytic units (LU20/107 effector cells). Non‐adherent monocyte‐depleted PBMC and natural killer (NK) cells purified by negative selection mediated significantly higher levels of ADCC than unseparated PBMC against SCCHN targets. NK cells, defined as CD3‐CD56' cells, could be effectively armed by cMAb SF‐25, as confirmed by flow cytometry and ADCC assays. IL2‐activated armed NK cells mediated higher levels of ADCC than non‐armed NK cells. Binding of cMAb SF‐25 to NK cells and their ADCC were enhanced by pre‐incubation with polyethylene glycol. Arming of NK cells with chimeric antibodies should be considered in developing novel strategies for treatment of human SCCHN, especially in the adjuvant setting. © 1995 Wiley‐Liss, Inc.

Nude mice carrying human squamous‐cell carcinoma xenografts were given i.v. injections of radiolabelled monoclonal antibodies (MAbs). MAb E 48, which reacts with squamous‐cell carcinomas, was labelled with 131l,while a second control MAb of similar immunoglobulin subclass was labelled with 125l. Both antibodies were injected simultaneously, then the mice were scanned with a gamma camera or their tissues were removed and antibody uptake was calculated as a percentage of the injected dose. Uptake of E 48 reached a peak value of 16%/g on day 3, while uptake of the control antibody was less than 1.8%/g. By 24 hr after injection tumor could be visualized without subtraction techniques. At days 3 and 7, only xenografts were visible on imaging. These findings suggest that E 48 is capable of high specificity in targeting isotopes to squamous‐cell carcinomas in an experimental setting.

The anti‐tumor activity of the putative differentiation‐inducing agent dimethylformamide (DMF) was assessed in 7 head‐and‐neck xenograft (HNX) lines transplanted into nude mice. The drug was administered intra‐peritoneally at the maximum tolerated dose. A significant growth‐inhibitory effect was observed in 3 out of 7 tumor lines tested. When compared with 5 conventional drugs active in patients with squamous‐cell carcinoma of the head and neck (HNSCC), DMF was as effective as the most active drugs (cisplatin and bleomycin). The most sensitive xenograft line, the poorly differentiated tumor HNX‐14C, was used to test the hypothesis that differentiation induction might play a role in the antitumor activity of DMF. Light microscopic examination did not show clear‐cut alteration of differentiation characteristics such as keratin and keratin pearl formation. Furthermore, we used a monoclonal antibody to study the expression of cytokeratin 10 which is useful as a differentiation marker of human HNSCC tumors. Keratin 10, not present in HNX‐14C tumors grown under control conditions, became expressed in some cells upon DMF treatment. Further evidence for a differentiation‐inducing activity of DMF was found in electron‐microscopic studies. In treated HNX‐14C tumors, in addition to cells with normal ultrastructural features, better‐differentiated cells were observed, as manifested by an increase in the number of tonofilaments and desmosomes. The results show that DMF has a potential value for the treatment of patients with head‐and‐neck cancer, and that differentiation induction might play a role in the anti‐tumor action of the drug.