Expression of tenascin-C in intraductal carcinoma of human breast: relationship to invasion.

Tenascin-C (Tn-C) is an extracellular matrix glycoprotein that appears in areas of epithelial-mesenchymal interaction during fetal development and in neoplasia. The immunohistochemical expression of Tn-C and its relationship to histology, nuclear grade, microinvasion, oestrogen (ER) and progesterone receptors (PR), and to cell proliferation measured by Ki-67 expression were studied in 89 intraductal breast carcinomas (DCIS). Periductal Tn-C was noted in 87% and stromal Tn-C in 25% of the tumours. Stromal expression was associated with moderate to strong periductal expression and microinvasion. Periductal expression was associated with comedo-type, nuclear grade, microinvasion, Ki-67 expression, and lack of PR. The distribution of Tn-C was compared in DCIS and in the intraductal component from another series of small axillary node-negative invasive breast carcinomas (n = 44). Tn-C was present in the stroma of pure DCIS in 25% and in the intraductal component of the other series in 82%. Thus, stromal or moderate to strong periductal Tn-C expression in DCIS may relate to early invasion. DCIS with weak periductal or missing Tn-C expression may be a subgroup with benign behaviour.