Tenascin patterns of expression in duct carcinoma in situ of the breast.

Immunohistochemical methods were used to study tenascin (TN) expression in duct carcinoma in situ (DCIS) of the breast of different histologic types. We evaluated 82 lumpectomy specimens of DCIS. There were 5 cases of comedo type, 19 cases of noncomedo type, and 58 cases of mixed comedo and noncomedo type. In 44 cases, the intraductal carcinomas were associated with infiltrating (invasive) duct carcinoma. TN expression was studied by immunohistochemical methods using monoclonal mouse anti-human tenascin (DAKO-TN2M636; 1:50 dilution). Positivity was recorded on a scale of 0 to 2+ for presence of TN staining around tumor ducts and thickness of TN-stained fibrous bands. TN showed positive correlation between thick bands around comedo DCIS and thin bands around noncomedo DCIS. The TN score had statistically significant positive association with high nuclear grade (p 0.004), periductal inflammatory infiltrate of DCIS (p 0.0006), associated extensive central necrosis of DCIS (p 0.0005), and comedo DCIS (p 0.0004). TN expression in the stroma was positively associated with tumor size (p 0.00002), extensive central necrosis (p 0.02), comedo DCIS (p 0.0005), and associated invasive carcinoma (p 0.006). The TN score did not correlate with duct size, multicentric carcinoma, or associated microcalcification. These results demonstrate the different biological nature of DCIS comedo type and suggest its preinvasive potential.