Antonia Strippoli

The combination of perioperative chemotherapy plus complete surgical resection is currently accounted as the first-choice strategy in patients with locally advanced Gastric Cancer (LAGC). Nevertheless, the partial response rate makes it necessary to search biological parameters useful to select patients who would benefit most from neoadjuvant chemotherapy (NAD-CT). We performed a retrospective analysis on a cohort of 65 LAGC cases, EBV negative and without MMR defect, submitted to perioperative chemotherapy plus surgical resection. We evaluated the neutrophil-lymphocytes ratio (NLR) in peripheral blood, the TILs density (reported as CD4/CD8 tissue ratio) and PD-L1 expression by immunohistochemistry on bioptic tissues before the treatment. Results were correlated with the biological features, histological response (TRG) and clinical outcome (PFS and OS). We found that NLR, TILs and PD-L1 expression showed a significant correlation with TNM stage, lymphovascular invasion and response to NAD-CT (TRG). Correlating the NLR, TILs and PD-L1 expression with PFS and OS, we found that patients with lower NLR levels (< 2.5 ratio), lower TILs (< 0.2 ratio) and higher PD-L1 level (CPS ≥ 1) had a significantly better PFS and OS than those with higher NLR, higher TILs and lower PD-L1 expression (p < 0.0001). Multivariate and multiple regression analyses confirmed the predictive and prognostic role of all three parameters, especially when all three parameters are combined. Our study demonstrated that pre-treatment NLR, TILs and PD-L1 expression are predictive and prognostic parameters in NAD-CT-treated LAGC suggesting a pivotal role of the systemic and tumor microenvironment immunological profile in the response to chemotherapy.

Alterations in the transcriptional factor c-MYC could be involved in the anti-EGFR resistance in metastatic colorectal cancer (mCRC). The c-MYC expression was evaluated in 121 RAS and BRAF wild-type mCRC before treatment with anti-EGFR+Folfiri therapy and in 33 subsequent metastases collected during target therapy (TT) or in TT resistance phase. We analyzed the expression and the functional role of some c-MYC linked miRNAs (miR-31-3p, miR-143 and miR-145) in our patient group and in two CRC cell lines, also performing a c-MYC target PCR array. Patients with higher c-MYC expression (HME) showed a significant lower PFS and OS when compared to those with low c-MYC expression (LME). HME pattern was significantly more frequent in the metastases after TT and significantly associated to anti-EGFR molecular resistance alterations. We also found a significant correlation between the expression of the above-mentioned c-MYC linked miRNAs, c-MYC level and anti-EGFR resistance. Moreover, expression gene profiling pointed out the pivotal role of c-MYC in CRC-related cell-cycle, apoptosis, signal transduction and cell-growth pathways. c-MYC expression might distinguish patients with a lower PFS and OS in anti-EGFR treated mCRC. The individuation of some miRNAs involved in the c-MYC pathway regulation and the downstream c-MYC effector genes could provide a new possible target to overcome the anti-EGFR resistance in mCRC.