Analysis of PTEN gene by fluorescent in situ hybridization in renal cell carcinoma.

Objective: To evaluate the frequency of deletion of the PTEN gene in renal cell carcinoma (RCC) and its impact on the rates of overall and disease-free survival.

Methods: We analyzed 110 patients with renal cell carcinoma who underwent radical or partial nephrectomy between 1980 and 2007. In 53 cases it was possible to analyse the PTEN gene by the method of fluorescent in situ hybridization using the technique of tissue microarray. For statistical analysis, patients were classified in two groups according to the presence or absence of the deletion.

Results: The mean follow-up time was 41.9 months. Hemizygous deletion was detected in 18 patients (33.9%), while the homozygous one was present in three (5.6%). Deletion was present in approximately 40% of the analyzed cases. Monosomy and trisomy were detected in nine (17%) and two patients (3.8%), respectively. In 21 patients (39.6%) the analysis of the PTEN gene by in situ hybridization was normal. There were no statistically significant differences in overall (p = 0.468) and disease-free (p = 0.344) survival rates between patients with or without deletion. Factors which were independent for overall survival: TNM clinical stage, symptoms at diagnosis, high Fuhrmann grade, performance status (ECoG) and tumor recurrence. Disease-free survival was influenced only by the clinical TNM stage.

Conclusion: Deletion of the PTEN gene in RCC was detected with a frequency of approximately 40% and its presence was not determinant of lower survival rates, the traditional prognostic factors remaining as determinants of outcome.