EXPRESSION OF P16 MUTANT PROTEIN AND KI67 IN CUTANEOUS AND NON-CUTANEOUS MELANOMA

ABSTRACT Objective: To determine expression of p16 mutant protein and ki67 in cutaneous and non-cutaneous melanoma. Study Design: Cross sectional study. Place and Duration of Study: Armed Forces Institute of Pathology, Rawalpindi, from July 2017 to July 2018. Methodology: All cases of melanoma diagnosed by histopathological examination were included. P16 and ki67 antibodies for immunohistochemical studies were applied in all cases. Patient's gender, age, tumor site and results of immunohistochemical(IHC) stains were noted. Results: A total number of 40 cases of melanoma were studied. It was more common in males 28(70%) than females 12(30%). Mean age of presentation was 51.1 ± 1.17 years. Most of the patients i.e., 25(62.5%), were in age group above 50 years, Cutaneous melanoma was the commonest type being 22(55%), followed by ocular melanoma being 14(35%) and mucosal melanoma 4(10%). The immunohistochemical staining for p16 was positive in all cases(100%). Ki67 proliferative index was high in most cases 34(85%). It was low in the rest of cases being 6(15%). Conclusion: Melanoma was found more common in males in the age group above 50 years. Cutaneous melanoma was the most common type. There was strong correlation between p16 and ki67 expression. P16 was seen in all cases. High ki67 was seen in 85% of cases.