SIRT1 and Ki67 immunohistochemical expression in progression of cutaneous malignant melanoma

The current study evaluated the proliferation index and immunohistochemical expression of SIRT1 on normal skin and cutaneous melanocytic nevi (CMN) and cutaneous malignant melanoma (CMM). Formalin-fixed paraffin-embedded tissue samples from 43 CMN, 22 CMM and 10 normal skin were obtained and clinical data were abstracted from the electronic medicalrecord.SIRT1 and Ki67 proteins expressions were evaluated regarding to clinic pathological behavior in CMM. The level of significance was set at α = 5% (p < 0.05).Our findings showed that SIRT1 positivity was significantly higher in benign melanocytic nevi than that in cutaneous malignant melanoma (p=0.002). As expected, the proliferation index was significantly higher in samples of cutaneous malignant melanoma as compared to the normal skin and melanocytic nevi (p=0.001). However, the expression of Ki67 protein was not also significantly related to the expression of SIRT1 (p > 0.05). In conclusion, low expression of SIRT1 and high proliferation index may play an important role in progression of cutaneous melanoma.