RESUMO
INTRODUCTION: The current challenge on renal cell carcinoma (RCC) is to finding a non-invasive biomarker for improving their diagnostic and therapeutic management. In the present study, we analyzed the clinical value of plasma levels of cell-free DNA (cfDNA) and RNA (cfRNA) of two genes: glyceraldehyde 3-phosphate-dehydrogenase (GAPDH) and human telomerase reverse transcriptase (hTERT). MATERIALS AND METHODS: We recruited 82 patients with RCC, and 20 healthy subjects. Using RT-PCR techniques, plasma levels of cfDNA and cfRNA from hTERT and GAPDH genes were quantified pre- and post-operatively, and one year after surgery. Relationships between such plasma levels and clinicopathological features and evolution of disease were analyzed. RESULTS: Levels of GAPDH cfDNA and cfRNA were significantly higher in patients than in healthy subjects. hTERT cfDNA was detected in plasma from 35% of RCC patients and in none healthy subject. At diagnosis, plasma levels of GAPDH cfDNA were higher in advanced pT and TNM stages, and hTERT cfDNA in patients with 3-4 Fuhrman grade and affected lymph nodes. Levels of cfNAs were not related to the presence of metastasis. Following nephrectomy, GAPDH cfDNA levels dropped, and patients with higher levels before and after nephrectomy, showed lower overall survival (OS). However, Cox's multivariate model did not prove any association of the cfNA levels with progression. CONCLUSION: Plasma levels of cfDNA from GADPH and hTERT genes were correlated to tumor diagnosis and progression and, thus, such analyses might help to diagnosis and prognosis of RCC patients.
RESUMO
INTRODUCTION: Elevated mRNA expression of human telomerase reverse transcriptase (hTERT mRNA) is common in many types of tumors, participating in tumor growth and progression. Such expression has not been sufficiently examined in renal cancer. The goal of the present study was to quantify it and analyze its possible clinical value in the management of this pathology. PATIENTS AND METHODS: The study included 111 patients who underwent surgery for renal cell carcinoma (RCC) between 2015 and 2017. Tumor samples were taken from all patients and, in 94 of them, healthy renal tissue adjacent to the tumor was also sampled. The 2 types of tissue were histologically confirmed, after which mRNA was extracted. Using real-time quantitative PCR, the expression of hTERT and glyceraldehyde-3-phosphate dehydrogenase (as endogenous control) were indirectly quantified using the crossing point (CP), which is inversely correlated with the number of sample replicates yielding positive results. These values were correlated with patient socio-demographic variables and clinical-pathological factors of the RCC. RESULTS: The majority of patients were males, with an average age of 60.5 years (SD: 14.02). Most tumors (69.4%) were clear cell carcinomas. The most frequent stages were pT2 or lower (73%), while 5% were pN1 and 12% pM1. The majority of tumors (58%) were Fuhrman grades 1 or 2 (low grade). All samples of tumor and nontumor tissue expressed glyceraldehyde-3-phosphate dehydrogenase mRNA, with the CP in the tumor sample significantly lower than in the nontumor tissue (P < 0.001). The expression of hTERT mRNA was detected in 68% of tumor tissues and significantly correlated with histopathology: 100% in sarcomatoid RCC and 77.9% in clear cell carcinomas (P < 0.0001). The CP was lower in pN1 (Pâ¯=â¯0.018), pM1 (Pâ¯=â¯0.046), and TNM IV stages (Pâ¯=â¯0,041). A greater number of hTERT mRNA replicas were detected in M1 patients (Pâ¯=â¯0.0005) and TNM IV stage (Pâ¯=â¯0.017). There was no correlation of hTERT mRNA expression with Fuhrman grade. CONCLUSIONS: The quantitation of hTERT mRNA expression in RCC might be useful as a complementary diagnostic tool as well as for assessing aggressiveness of the tumor.
