When the two most frequent histological subtypes of melanoma, such as SSM and NM, were individually analyzed, a significant increase in the frequency of MICA*009 allele was observed in both groups of patients compared with controls (25% in SSM and 35% in NM versus 15% in controls; P = 0.016 and P = 0.015, resp). The gene discussed is MICA; the disease is melanoma.