Immunohistochemical demonstration of keratin 7 in routinely fixed paraffin‐embedded human tissues

Abstract

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.

Establishment of new ovarian and colon carcinoma cell lines: differentiation is only possible by cytokeratin analysis

“…This reflects exactly the situation in corresponding in vivo carcinomas (Moll et al, 1982;Osborn et al, 1986;van Niekerk et al, 1991): colon carcinomas are essentially CK 7 negative (for exceptions, see van Niekerk et al, 1991;Moll et al, 1993); ovarian carcinomas are constantly positive. This was confirmed by our study.…”

Primary Seminal Vesicle Carcinoma: An Immunohistochemical Analysis of Four Cases

“…This coordinate CK7/CK20 immunophenotype is similar to carcinomas that show ductal-type differentiation, such as breast and prostatic adenocarcinoma (3,(25)(26)(27)(28). Therefore, in the region of the seminal vesicles, a CK7/CK20 immunophenotype alone would not distinguish SVCA from prostatic adenocarcinoma.…”

“…CK7 and CK20 are subsets with restricted expression depending on the type and differentiation of the epithelium (27,28). CK7 is characteristic of ductaltype differentiation and is expressed in a variety of adenocarcinomas, such as breast, ovarian (nonmucinous), and prostatic (27). Notably, it is absent in colorectal adenocarcinoma.…”

Cytokeratin 7 and Cytokeratin 20 Expression in Epithelial Neoplasms: A Survey of 435 Cases

“…Its expression is often seen in the major categories of adenocarcinoma, including adenocarcinoma of the breast, lung, ovary, endometrium, thyroid, salivary gland, pancreas, and bile duct (21,25,26). However, there are circumstances in which the determination of CK 7 positivity is useful.…”