Immunohistochemical detection of keratin, actin and type IV collagen in serial sections of methacarn-fixed breast cancer tissues.

Abstract

Correlations among the immunolocalizations of keratin, actin and type IV collagen were investigated in serial sections of methacarn-fixed, paraffin-embedded mastectomy specimens taken from infiltrating breast cancer patients. Stainings of the filaments in pretreated sections with actinase were often weaker and/or less apparent in cancer cells than in normal mammary gland cells. If at least 30% of living cancer cells were stained, the case was scored positive. Positivity for 312C8-1 specific for basal cell type keratin 14 was observed in 8 of 60 cases, while for NCL-5D3 specific for luminal cell type keratins, positivity was observed in 57 of 60 cases. Five cases positive for HHF35 specific for muscle actin were also positive for 312C8-1 and NCL-5D3. Type IV collagen in cancer foci was patchy and/or absent, but small cancer nests surrounded completely by continuous type IV collagen, termed “in situ carcinoma components” were found in 25 of 60 cases. In all the components, stainings with 312C8-1 and/or NCL5D3 were found in some cancer cells, and the former was almost always seen in a basal orientation within the components. In con- clusion, keratin 14-positive basal cells could be identified in paraffin sections, and these findings suggest that the basal cells are closely related to continuous type IV collagen and a progressive loss of the cells may promote metastasis through fragmented type IV collagen.