EXPRESSION OF BETA-1 INTEGRINS ON TUMOR-CELLS OF INVASIVE DUCTAL BREAST-CARCINOMA

The integrins are transmembrane alfabeta heterodimers mediating cell-c ell as well as cell-extracellular matrix interactions. The present stu dy was designed to analyse the expression of beta-1 integrins on cryos tat sections of invasive ductal carcinomas not otherwise specified by avidin-biotin complex immunoperoxidase technique, and to compare it wi th the morphometric prognostic index (MPI). The results show that the expression of beta-1 integrins is heterogeneous in the tumors. This he terogeneity was observed in quantitative and qualitative staining patt ern. There was an absent expression of beta-1 integrins in 22 out of S S tumors while 33 showed staining, weak on 23 cases and strong on 1 0 infiltrative ductal carcinomas. Statistical analysis pointed to some c orrelation of beta-1 integrins with some morphometric parameters. Low or absent expression of beta-1 integrins correlated significantly with tumors exceeding 2 cm (p < 0.0245). Moreover, a larger Proportion of tumors with positive lymph nodes showed absence of beta-1 expression c ompared with negative lymph node, and this was also statistically sign ificant (p < 0.0076). Correlation between mitotic activity index and s taining intensity for beta-1 integrins was not found (p < 0.372). When tumors with different beta-1 expression were subdivided according to MPI values into two groups, one group with a low-risk, < 0.6, and seco nd with a high risk, > 0.6, concordance in prognostic value was shown between MPI and beta- 1 expression (p < 0.0193). These results support the idea that loss of beta-1 integrins correlates with the invasive a nd metastatic potential of tumor cells.