Expression of pS2 protein in breast cancer and its relation with estrogen receptors and progesterone receptors

BACKGROUND: We studied pS2 protein in breast tumors and its relation with estrogen and progesterone receptors and with anatomopathological characteristics of the tumors. MATERIAL END METHODS: We measured the pS2 content (by IRMA) and steroid receptors content (by EIA) in 151 breast tumors. Results were compared and correlated with tumoral characteristics. RESULTS: 53% of tumors were pS2+, Among them, 91% were estrogen receptors +. 86% of estrogen receptors negative tumors were pS2-. We observed correlation between pS2 and estrogen receptors values (r = 0.56; p < 0.0001) and between pS2 and progesterone receptors values (r = 0.53; p < 0.0001). Distributing the tumors in pS2+ and pS2-, we observed associaton between pS2+ and estrogen receptors + (chi(2) = 45.6; P < 0.0001) and pS2+ and progesterone receptors + (chi(2) = 43.1; P < 0.0001), However, we found a 18.5% of estrogen receptors + pS2- tumors. We observed a significant difference between GII and GIII tumoral grades (chi(2) = 5.51; p < 0.019), with a majority of pS2+ tumors in GII and pS2- tumors in GIII. CONCLUSIONS: The estrogen receptors in estrogen receptors + ps2- tumors may be non functional. The presence of pS2 protein alternative to that of progesterone receptors may indicate a functional heterogeneity of the estrogen receptors system, which is of interest in evaluating prognosis and response to the hormonal therapy.