VALIDATION OF PREDICTIVE AND PROGNOSTIC BIOMARKERS AS A GUIDE FOR A PERSONALIZED APPROACH IN SOLID TUMOURS

Breast cancer (BC), Colorectal Cancer (CRC) and Non-Small Cell Lung Cancer (NSCLC) are among the most commonly diagnosed solid tumors, and occupy the first places in the mortality rankings. Compared to an old fashioned one-size-fits-all approach, precision medicine offers the possibility to accurately choose the most appropriate therapeutic strategy, that fits the patients not only from the clinical (age, comorbidities) but also from a molecular point of view. A genetic and biological understanding of the tumor, integrated with a weighted analysis of results can help the clinician in designing a therapeutic pathway that, ideally from the start, gives the patients the best response rates. The aim of my research is to evaluate the markers that have the greatest impact on the prediction of therapy response. Mutational analysis revolutionized the NSCLC treatment paradigm and, consequently, improved the prognosis. EGFR mutated patients benefit from target therapy with tyrosine kinase inhibitors. A fluid and longitudinal monitoring of mutational status is becoming a key factor in disease management. Firstly we extracted circulating free DNA (cfDNA) from the plasma of 30 patients with EGFR-mutated NSCLC and assessed mutational status with real-time PCR. We then monitored such mutation during target therapy in 19 patients. The liquid biopsy had a sensitivity of 60% in confirming the tissue mutation. Patients whose EGFR mutation was not detectable on plasma had a longer Progression free survival (PFS) and Overall survival (OS). Next step will be assessing if cfDNA analysis allows early detection of resistance mutation such as T790M. Next part of my research focused on luminal BC, working partially retrospectively on data from a phase III study of 90 ER-positive, HER2 negative locally advanced breast cancer patients that were randomly assigned 1:1 to receive Let 2,5 mg daily and metronomic oral Cyc 50 mg daily with (arm B; n=45) or without (arm A, n=45) sorafenib 400 mg/bid daily for six months as neoadjuvant treatment. The predictive role of Ki67, SUV variations and metabolic response and its changes with regards to clinical response and survival was analyzed. The serum of 32 patients was analyzed via Luminex Multiplex Panel technology. 38 analytes (cytokines and growth factors) were simultaneously measured according to arm of treatment and time of sample collection (before and after treatment). Patients were divided into groups according to response to therapy (RECIST). Then we investigated a possible link between chemotherapy-induced RNA disruption and survival/progression. Analysis were performed on 40 biopsies taken at baseline and 15 days after the beginning of the neoadjuvant therapy. The RNA for each sample or subdivided sample was then assessed using the RNA Disruption Assay. The maximum RNA disruption Index (RDI) value for each patient at day 15 was used for all analyses. Finally, We investigated the discordance of mutational status between primary and metastatic site in colorectal cancer.Patients with metastatic CRC who underwent surgery of both primary and metastasis were retrospectively evaluated, and mutational status assessment of K-RAS, N-RAS, BRAF and PIK3CA was performed on 21 patients. Median DFS was 20.5 months (95% CI 9.9-29.6) in patients with concordance in mutational status versus 10.4 months (95% CI 6.1-not reached) in patients with discordance (p=0.01) and median OS was 35.9 months (95% CI 26.3-not reached) in patients with concordance in mutational status 25.6 months (95% CI 6.6-not reached) in patients with discordance (p=0.038). In conclusion discordance seems related to clinical outcome. Overall my results show that new strategies and technologies allow the researchers and the clinicians to strive for a better and more complete understanding of solid tumors complex evolution, an integrated and focused approach to the early disease could become the future of disease management.