Researchers of the Kidney Physiopathology group from the CIBBIM-Nanomedicine at Vall d'Hebron Institute of Research (VHIR), in collaboration with the Urology Service of and the Pathological Anatomy Service of the Vall d'Hebron University Hospital, have identified for the first time a new biomarker, the pSTAT-3 Ser727, present in tumors of clear cell renal cell carcinoma (ccRCC), which predicts the survival of patients. The study, published in Cancer Research, may represent a paradigm shift in the care and treatment of patients.

"The apparently benign tumor can be as serious as the most invasive one if the biomarker levels are high", warned Dr. Anna Meseguer, leader of the group, after confirming the results obtained in vitro in a cohort of 98 ccRCC patients treated at Vall d'Hebron, with more of five years of clinical follow-up. From the presence of the biomarker in a tumor sample, researchers found that "tumors classified in the same risk group and apparently similar can behave very differently and determine the survival of patients, which can vary between 17 and 70 months", according to the lead author of the study, Dr. Meseguer.

An undetected cancer, until now

The ccRCC is the most aggressive and frequent cancer among all the subtypes of renal cancer and it is characterized by a lack of signs, symptoms or biochemical abnormalities that make the detection difficult. There are neither diagnostic nor prognostic tools available and most of the cases are detected by surprise: "nearly the 30% of patients with ccRCC are diagnosed too late and incidentally, when they have a screening test for the study of other symptoms", assured Dr. Enric Trilla, doctor from the Urology Service at Vall d'Hebron. And in these cases, he regrets that "it is too late because they have already developed metastasis and the mortality rate is up to the 95%". Besides this group of patients, the doctor added that "one third of the patients with localized ccRCC tumors who are treated with nephrectomy (removal of the kidney) also develop metastasis in the following months after surgery".

The diagnosis and monitoring of ccRCC requires continuous and expensive imaging tests that do not make possible the early diagnosis or the prediction of the tumor's evolution. For that reason, doctors do not have reliable biomarkers to recommend which is the best treatment: total or partial nephrectomy, immunomodulatory treatments or antiangiogenic therapies.

With the discovery of the patented pSTAT-3 Ser727 biomarker, researchers aim to develop a system for its implementation in the routine tests: "the use of the biomarker in the clinical practice would help us to stratify and monitor patients, as well as to choose the most accurate treatment, according to the levels of the biomarker", Dr. Trilla reported.