Prognostic impact of immune-microenvironment in colorectal liver metastases resected after triplets plus a biologic agent: A pooled analysis of five prospective trials.

BACKGROUND: Immune-contexture of tumour microenvironment (TME) influences prognosis of colorectal cancer (CRC) patients and can be altered by cytotoxic and targeted agents. Limited data are available regarding the immune-TME of CRC after treatment. METHODS: An extensive immunohistochemistry evaluation of immunological parameters on tumour cells and TME of colorectal liver metastases from 106 patients who underwent secondary resection, after receiving triplets FOLFOXIRI (5-fluorouracil, oxaliplatin and irinotecan) or COI (capecitabine, oxaliplatin and irinotecan) plus bevacizumab (N = 59) or cetuximab (N = 47) in five first-line no-profit clinical trials was performed. RESULTS: No substantial differences were reported in immunological parameters according to administered targeted agent, RAS/BRAF mutational status and histopathological or Response Evaluation Criteria in Solid Tumours response. Stromal expression of Cyclooxygenase-2 (COX-2) (p = 0.002), Human leukocyte antigen (HLA) (p = 0.003) and Programmed cell death protein 1 (PD1) (p = 0.002) were independent prognostic factors for longer relapse-free survival (RFS) at multivariate analysis with a positive trend for post-resection overall survival (OS). Patients whose metastases expressed stromal COX-2, HLA and PD1 (inflamed-score positive) reported longer RFS (25.5 versus 9.8 months; p < 0.001) and post-resection OS (64.3 versus 37.7 months; p = 0.003) as compared with others. In addition, patients with higher expression of CD4 and CD8 T-cells in tumour core and invasive margin (CD4/CD8-score) showed a better post-resection OS (not-reached versus 41.6 months; p = 0.032). A combined score of inflamed-score and CD4/CD8-score (combo-score) showed a clear prognostic role. CONCLUSIONS: The present study emphasises the role of immune-TME as independent predictor of survival in patients resected after triplets plus biologic. Inflamed-, CD4/C8- and combo-scores should be confirmed as prognostic factors in further studies.

Receptor tyrosine kinase and downstream signalling analysis in diffuse malignant peritoneal mesothelioma.

Our aim was to assess the activation profile of EGFR, PDGFRB and PDGFRA receptor tyrosine kinases (RTK) and their downstream effectors in a series of cryopreserved diffuse malignant peritoneal mesothelioma (DMPM) surgical specimens to discover the targets for drug inhibition. We also made a complementary analysis of the cytotoxic effects of some kinase inhibitors on the proliferation of the human peritoneal mesothelioma STO cell line. We found the expression/phosphorylation of EGFR and PDGFRB in most of the tumours, and PDGFRA activation in half. The expression of the cognate ligands TGF-α, PDGFB and PDGFA in the absence of RTK mutation and amplification suggested the presence of an autocrine/paracrine loop. There was also evidence of EGFR and PDGFRB co-activation. RTK downstream signalling analysis demonstrated the activation/expression of ERK1/2, AKT and mTOR, together with S6 and 4EBP1, in almost all the DMPMs. No KRAS/BRAF mutations, PI3KCA mutations/amplifications or PTEN inactivation were observed. Real-time polymerase chain reaction revealed the decreased expression of TSC1 c-DNA in half of the tumours. In vitro cytotoxicity studies showed the STO cell line to be resistant to gefitinib and sensitive to sequential treatment with RAD001 and sorafenib; these findings were consistent with the presence of the KRAS mutation G12D in these cells although it was not detectable in the original tumour. Our results highlight the ligand-dependent activation and co-activation of EGFR and PDGFRB, as well as a connection between these activated RTKs and the downstream mTOR pathway, thus supporting the role of combined treatment with RTK and mTOR inhibitors in DMPM.