Integrins are transmembrane receptors that modulate cell adhesion. Each is a heterodimer of varying α and β subunits. In malignancy, loss of integrin expression may result in less adhesive cells more likely to metastasize. Our aim was to characterize the integrins in human breast tissue and to examine the relationship between integrin expression and nodal metastasis in breast cancer.

Cryostat sections from 12 benign and 61 malignant (50 ductal and 11 lobular) samples were stained by the avidin-biotin complex method with monoclonal antibodies to the β1, β3, β4, and β5 subfamilies. All slides were read by two independent assessors with consensus agreement. Integrin expression was compared to variables by using the chi-squared test with Yates' correction and multivariate analysis based on logistic regression.

All integrin subunits studied were significantly reduced on breast cancer compared with benign cells (chi-squared test) but were not related to tumor differentiation. Loss of α1β1, α2β1, α3β1, α6β1, αvβ1, and αvβ5 were related to the presence of axillary metastasis. Independently the integrins were of limited clinical value as predictors of axillary spread. However, on multivariate analysis the combination of β1, αv, α1, tumor size, and vascular invasion gave a cumulative overall accuracy in predicting nodal disease of 97%.

Integrin expression is reduced in breast cancer and may explain tumor progression. Measuring the integrins might thus provide a means of selection for aggressive axillary treatment.