The predictive role of the immune system for response to therapy and survival in patients with solid tumors.

First of all I used an in silico approach (cBioPortal) to investigate possible correlations between survivals of patients with solid tumors and genomic alterations, using the gene list from the 770 immune-related PanCancer IO 360TM panel. Secondly through an in vitro analysis, 62 Paraffin-embedded formalin fixed (PEFF) samples of MMe were analysed for TILs and PD-L1 expression. Patients were divided in 4 groups according to a cut-off of the percentage of TILs found per sample as measured by means of immunohistichemistry: “0” or absent (between 0% and 5%), “1” or low (between 6% and 25%), “2” or moderate (between 26% and 50%) and “3” or high (between 51% and 75%). Higher expression of peritumoral TILs (Group 2 + 3) versus Group 0 and 1 correlated with improved OS (p-value = 0,02). On the contrary, PD-L1 expression seemed to be inversely correlated with clinical outcomes, even in the absence of statistical significance (HR: 1.76; p=0.083 95% IC: 0.92-3.36 in areas within the tumour; HR: 1.60; p= 0.176 95%; IC: 0.80-3.19 in areas within the stroma). No relationship between TILs and PD-L1 expression was identified. Thirdly we investigated the correlation between the prognosis of 12 PDAC patients and the presence of TILs through IHC and the expression of 521 immune system genes using Nanostring nCounter Vantage and related bioinformatics. Twenty immune system genes were significantly differentially expressed in patients with a good prognosis relative to patients with a worse prognosis: TLR2 and TLR7 (Toll-like receptor superfamily); CD4, CD37, FOXP3, PTPRC (B cell and T cell signalling); IRF5, IRF8, STAT1, TFE3 (transcription factors); ANP32B, CCND3 (cell cycle); BTK (B cell development); TNF, TNFRF1A (TNF superfamily); HCK (leukocyte function); C1QA (complement system); BAX, PNMA1 (apoptosis); IKBKE (NFκB pathway). Differential expression was more than twice log 2 for TLR7, TNF, C1QA, FOXP3, and CD37. To find a biomarker that could be a good prognostic factor and a predictor of response to anti-cancer treatments for predicting survival of breast cancer patients I have reviewed the literature and implemented a meta-analysis on the role of PIK3CA mutational status in randomized clinical trials. Overall 1929 BC cases were included. The pooled analysis confirmed that the presence of a PIK3CA mutational status represents an independent negative prognostic factor (HR = 1.67, 95% CI: 1.15-2.43; p = 0.007) in BC, as previously reported. To investigate immune-related biomarkers for predicting response to everolimus therapy in HR+/HER2- in vitro, I have analysed neutrophil and platelet to-lymphocyte ratios (NLR and PLR), immune pathways, and TILs in clinically and molecularly characterized HR+/HER2- BC and explored a correlation with the therapeutic strategy targeting mTOR through everolimus in 2131 metastatic patients from the BALLET study, in 23 patients receiving neoadjuvant everolimus and in 15 metastatic patients at the local institution, respectively. In the BALLET study quartiles of patients with lower NLR levels in the blood had higher survivals compared to patients with higher NLR: NLR ≤ 2.3 vs. NLR >2.3; NLR ≤ 3.2 vs. NLR > 3.2; and NLR ≤ 4.4 vs. NLR >4.4 (p=0.19, p=0.12 and p=0.01). In the smaller population of 15 metastatic patients, FACs analyses showed that everolimus responders vs. non-responders had higher levels of CD3+ T-lymphocytes at baseline (p=0.0343) and during treatment (p=0.0233), higher levels CD8+ and CD4+ T-lymphocytes at baseline (p=0.0172, p=0.0005, respectively) and during treatment (p=0.0102, p=0.0032, respectively); while they had slightly lower levels of regulatory T-lymphocytes and NKs (p=0.0588 and p=0.0411, respectively). The knowledge produced helps to define key immune-related pathways in solid tumors. Further refining a panel of immune-system markers could help guiding clinicians in the decision-making step for giving mTOR inhibitor everolimus in HR+/HER2- BC.