The immunoreactivity of OV-TL 12/30, a monoclonal anti-keratin 7 antibody (Mab), was investigated on frozen as well as paraffin-embedded human tissues. Its reactivity patterns were compared with another well-characterized monoclonal antibody to keratin 7 (RCK 105), and with broadly cross-reacting monoclonal (OV-TL 12/5) as well as polyclonal (pKer) keratin antisera. In frozen sections of normal and malignant human tissues both keratin 7 Mabs gave similar staining patterns. The immunoreactivity for OV-TL 12/30 and the polyclonal antibody (pKer) in tissue sections fixed in 4 per cent formalin or Bouin solution, was completely restored when pretreated with 0.1 per cent pronase, 0.1 per cent trypsin in phosphate-buffered saline (PBS) or with 0.5 per cent pepsin in 0.01 N HCl. Except for loss of immunoreactivity on human normal stomach surface epithelium and glandular mucous cells, Mab OV-TL 12/30 reacted strongly positive with essentially all those formalin- or Bouin-fixed paraffin-embedded tissues that had been shown to stain in non-fixed, frozen sections. In addition to the good correlation in human tissues, a complete correlation between the reactivity on frozen and paraffin-embedded human carcinomas (n = 86) was found as well. While both RCK 105 (anti-keratin 7) and OV-TL 12/5 (anti-keratin 5, 7, 14, 19) did not stain on paraffin-embedded sections, the polyclonal control antiserum (pKer) lost immunoreactivity in some cell types (e.g. mucous cells in compound glands, hepatocytes, pancreatic acinar cells, and proximal and distal convoluted tubules of the kidney). Our study shows that the keratin 7 Mab OV-TL 12/30 is an excellent marker for tumour histopathology since it is reactive in paraffin-embedded formalin-fixed human tissues.

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Objective. Ovarian and endometrial cancers coincide rather frequently in the same patient. Few data are available on the involvement of the specific morphological subtypes. To identify histological pathways in the synchronous occurrence, a population-based study was performed in The Netherlands. Methods. Using the national pathology database (PALGA) information of ovarian cancers and of earlier or later cancer in the endometrium was obtained. 5366 Patients were identified with primary malignant epithelial or borderline malignancy. Results. In 157 cases (2.9%) a new primary malignancy in the endometrium was diagnosed (146 within 1 year). The ratio of observed versus expected number of synchronous malignancy in the endometrium was estimated at 3.6 (95% CI: 2.7–4.7). Among 460 ovarian endometrioid carcinoma patients 53 cases showed a second primary endometrial cancer; 40 out of these 53 cases (75.5%) showed at both organ sites an endometrioid adenocarcinoma. Conclusion. These findings suggest an important role for the endometrioid subtype and prompt to mechanism-based studies incorporating molecular techniques.

Ovarian cancer and second malignant neoplasms are found to occur rather frequently in the same patient. From a clinical perspective, it is important to have quantitative information on concurrent malignancies in the same year of diagnosis of the epithelial ovarian cancer. In this population-based study, we used data from the Netherlands Nationwide Network for Registry of histo-and cytopathology (PALGA) and the Netherlands Cancer Registry (NCR). Data of the ovarian cancer as well as data on previous or later cancers were obtained. Agespecific cancer rates from the NCR were used to calculate expected numbers of cancer. Between 1987 and 1993, histopathology reports were identified of 4577 patients with primary epithelial malignant or primary borderline malignant ovarian cancers and its longitudinal data. As the database may lack detailed information on histopathology, a recent sample of 789 patients diagnosed with ovarian cancer in 1996-2003 was comprehensively studied as well. In the eventual data analysis of 5366 patients, 244 cases (4.5%) of concurrent primary malignancy were reported in the same year that the malignant epithelial ovarian tumor had been diagnosed against 51 expected. The observed vs expected ratio was 4.8 and the 95% confidence interval (CI) (4.3-5.5). For cancer of the uterus/endometrium the observed vs expected ratio was 62.3 (95% CI 52.5-73.5). For skin, breast, colorectal, urinary bladder, renal and cervical cancer the ratio was also larger than unity. The elevated risk of concurrent cancer may lead to clinical screening protocols. The findings on endometrial cancer may prompt research on common etiologies and biomarkers.

The immunoreactivity of OV-TL 12/30, a monoclonal antibody to keratin 7 was investigated on paraffin-embedded human lung cancer tissues of 61 patients. A modified AEC-immunoperoxidase method with pepsin pre-digestion was used. In normal lung tissue keratin 7 was found in bronchial and bronchiolar epithelium, pneumocytes and compound glands. Squamous metaplasia of the bronchial tree was negative. All 24 squamous cell carcinomas were negative irrespective of grade of differentiation. All differentiation grades of 20 adenocarcinomas including bronchioalveolar carcinomas were positive. Since six large cell anaplastic carcinomas did not react with keratin 7 antibody these tumours are considered to be of squamous cell rather than adenocarcinomatous origin. Small cell anaplastic carcinomas were negative in 10 of 11 cases. Our study demonstrates that this keratin 7 antibody is useful in differentiating between squamous cell carcinoma and adenocarcinoma of the lung and it may be particularly useful in making the correct diagnosis in small lung biopsy specimens.