PROLIFERATION AND HYPOXIA IN HUMAN SQUAMOUS-CELL CARCINOMA OF THE CERVIX - FIRST REPORT OF COMBINED IMMUNOHISTOCHEMICAL ASSAYS

Purpose: To characterize the distribution of hypoxia and proliferation in human squamous cell carcinoma of the cervix via an immunohistochem ical approach prior to initiation of therapy, Methods and Materials: P atients with primary squamous cell carcinoma of the cervix uteri recei ved a single infusion of the 2-nitroimidazole, pimonidazole (0.5 g/m(2 ) i.v.), and 24 h later punch biopsies of the primary tumor were taken , Tissue was formalin fixed, paraffin embedded, and sectioned for immu nohistochemistry. Hypoxia was detected by monoclonal antibody binding to adducts of reductively activated pimonidazole in malignant cells, S taining for endogenous MIB-1 and PCNA was detected in tumor cells via commercially available monoclonal antibodies, Point counting was used to quantitate the fraction of tumor cells immunostained for MIB-1, PCN A, and hypoxia marker binding, Results: Immunostaining for pimonidazol e binding was distant from blood vessels, There was no staining in nec rotic regions, and only minimal nonspecific staining, mostly in kerati n, In general, cells immunostaining for MIB-1 and PCNA did not immunos tain for pimonidazole binding, Cells immunostaining for MIB-1 and PCNA showed no obvious geographic predilection such as proximity to vascul ature, Quantitative comparison showed an inverse relationship between hypoxia marker binding and proliferation, Conclusions: Immunohistochem ical staining for pimonidazole binding is consistent with the presence of hypoxic cells in human tumors and may be useful for estimating tum or hypoxia prior to radiation therapy, Immunostaining for pimonidazole binding is an ideal complement to immunohistochemical assays for endo genous proliferation markers allowing for comparisons of tumor hypoxia with other physiological parameters, These parameters might be used t o select patients for radiation protocols specifically designed to off set the negative impact of hypoxia and/or proliferation on therapy, Th e inverse relationship between pimonidazole binding and proliferation markers is a preliminary result requiring verification, (C) 1997 Elsev ier Science Inc.