Tumor Infiltrating Lymphocytes in Different Stages of Malignant Melanoma

Backgrounds: Malignant melanoma is leading cause of skin cancer related death. Melanoma is one of the most immunogenic tumors causing significant body immune response. Tumor infiltrating lymphocytes (TIL) are an important part of this response. TIL are lymphocytes in close association with tumor cells that have infiltrated tumor nests.Purpose: To evaluate the relationship of TIL in malignant melanoma with stage of cancer and histopathological findings Methods: This was a retrospective cross sectional study. Records of patients with malignant melanoma in Razi dermatology hospital and cancer institute were used. Specimens were collected and reevaluated. Demographic information and histopathological findings was recorded for each patient. TIL was categorized to none, grade I, II and III based of quantity on infiltrating lymphocytes. Data were computerized and analyzed by SPSS. Logistic regression was used to compare variables among grades of TIL.Results: 111 patients with mean age of 59.33±14.68 and male to female ratio of 1.09 were recruited in our study. TIL was not seen in 17.1% of patients. Grade of TIL in all melanoma subtypes was I (47.7%), II (28.8%) and III (6.3%). Age and sex were not significantly different between different grades of TIL. Stage of cancer significantly decreased with increasing grade of TIL. (P value 0.00) Many histopathological findings were related to TIL but only microsatellitosis relation with TIL remained significant after adjusting for stage of cancer. (P value: 0.01)Conclusion: Increased density of TIL can show more effective body immune response against melanoma. This response can limit progress of the cancer and result in diagnosis of the tumor in lower stages.