Sex-associated miR-4286 is related to Breslow thickness and TILs in stage II/III primary cutaneous melanoma

Sex differences in melanoma incidence and mortality are well-established. Previous work has shown that the female survival advantage can be largely explained by differences in clinico-pathologic features, such as age, Breslow thickness, ulceration, mitoses, and primary site. Here we test the hypothesis that sex-differentiated expression of micro-RNAs (miRNAs) may be associated with sex differences in melanoma pathology. In a sample of 715 AJCC stage II/III primary melanomas from the InterMEL project, we find two miRNAs (miR-361 and miR-4286) that are differentially expressed in males and females, and further find one of these (miR-4286) to be associated with both greater Breslow thickness and the presence of brisk tumor infiltrating lymphocytes (TILs). These results suggest that miR-4286 may be a candidate marker for sex differences in melanoma pathology. Functional experiments may confirm whether this relationship is causal or purely associative.