Progesterone and estrogen receptors in conjunctival melanoma and nevi

Background Since it has been observed that melanocytic lesions can alter their appearance during pregnancy, we analyzed whether hormone receptors are expressed in conjunctival nevi as well as conjunctival melanoma. We further analyzed whether the number of estrogen (ER) or progesterone receptors (PR) might be associated with the disease course in conjunctival melanoma. Twenty-seven paraffin-embedded samples of conjunctival nevi and 27 conjunctival melanoma specimens were examined using immunohistological analysis with antibodies against PR and ER. The percentage of stained cells were analyzed, taking into account patient gender and age. Out of the melanoma group, all patients with complete data for tumor thickness, tumor localization, age at diagnosis, gender, and follow-up including recurrence, metastasis and tumor-related death were included in the second part of the study (n = 15), where hormone receptor rates were associated with tumor outcome, regarding recurrences, metastasis or death. Written consent was received from all included patients. Both nevi and melanomas showed high rates of PR- and ER-positive cells. In Nevi, 64 +/- 25 % of cells stained positive for PR and 35 +/- 34 % for ER. In melanoma specimens, 68 +/- 30 % showed PR and 44 +/- 34 % ER expression. Differences between men and women in expression rates were not statistically significant. Out of 15 melanoma patients (nine female, six male), 53 % (five women and three men) experienced 1-4 recurrences, and four patients developed metastases. The median estimated survival time was 12.2 years. A multivariate survival model taking into account known risk factors for prognosis in conjunctival melanoma confirmed tumor location to be an important predictive factor for outcome (p = 0.05). The rate of PR or ER did not show a statistically significant correlation with the disease course in our cohort. We observed that conjunctival melanocytic lesions express hormone receptors, which could explain why these tumors can alter their appearance under hormonal changes. Regarding the prognosis of conjunctival melanoma, no statistically significant correlation between hormone receptor expression and event-free survival was found in this analysis.