VHL gene mutation in patients with renal tumors

Objective: This study aimed to determine VHL gene mutations and the relation of these mutations to type and pathological stage of renal tumors.

Materials and methods: Forty patients (20 males, 20 females; mean age 59 years) who underwent ablative surgery for renal tumor prediagnosis between February 2009-November 2009 in of Ege University School of Medicine, Department of Urology were randomly selected. Twenty-nine of the patients underwent radical nephrectomy, 5 underwent partial nephrectomy, and 2 patients underwent laparoscopic radical nephrectomy. Four patients whose pathological outcome was not malign kidney tumor have been excluded from the study. Thirty-eight patients (21 males, 16 females; mean age 61 years) who underwent any surgeries in Department of Urology and showed no malignance suspicion in the same time period were included in control group. VHL gen mutations were analyzed preoperatively.

Results: According to 2002 TNM staging, 8 (22%) patients were T1a, 11 (31%) patients were T1b, 3 (8%) patients were T2, 9 (25%) patients were T3a, 3 (8%) patients were T3b, and 2 (6%) patients were T4 stage. Twenty-eight (78%) patients were N0, 5 (14%) patients were N1, and 3 (8%) patients were N2. Five (14%) patients was at M1 stage. Histologically, 18 (50%) patients had clear cell carcinoma, 3 (8.3%) patients had chromofob cell carcinoma, and 3 (8.3%) patients had papillary cell type 1 carcinoma. Genetic analysis showed that 6 individuals had heterozygote change described previously as mutation (Q167Q and V181V linked heterozygote in 2 patients, P61P heterozygote in 2 patients, L129L heterozygote in 1 patient, and P61P heterozygote in 1 patient). None of these changes resulted in the change of aminoacids.

Conclusion: VHL gene mutation was not detected in our study population, which may be result of the genetical characteristics of Turkish population or small sample size. The present study would be a pioneer for future studies on tumor tissue and VHL gene polymorphism in Turkish population.