Galectins role as predictive markers for anti-PD-1-based immunotherapy in non-small cell lung cancer.

111 Background: Checkpoint inhibitor-based immunotherapy is opening a promising scenario in oncology with objective responses registered in several tumors. However reliable predictive markers of tumor responsiveness are still lacking. These markers need to be urgently identified for a better selection of patients candidate to immunotherapy. In NSCLC setting, the pleiotropic molecules Galectin 1 and 3 regulate apoptosis and tumor immune-escape and are in the right position to play as predictive marker in anti-PD1 based immunotherapy. Methods: 27 consecutive patients with non small cell lung cancer (NSCLC) stage IV, treatment-naive, selected on the basis of PD-L1 tumor proportion score (TPS) ≥ 50 % were considered for immunotherapy with anti PD-1 antibodies as a first-line treatment. Patients assessments were conducted at baseline and after 3 cycles of therapy (week 12) and classified according to immune-related response criteria (iRECIST). Immunohistochemical analysis was performed on primary tumor biopsies before treatment in order to evaluate Gal-1 and Gal-3 expression both in cancer cells and tumor interstitium. Tumors were grouped in 2 different classes depending on the expression level of these molecules. Results: In our preliminary data there seems to be a strong correlation between the responses to anti-PD-1 treatment and a low-intermediate expression of intratumoral Gal-3 and interstitial Gal-1. In fact, all patients in the intratumoral Gal-3 low-intermediate expression group had an excellent response to immunotherapic treatment (10/10 patients), while 15/17 patients with high intracellular Gal-3 expression had clinical and radiographic progression of the disease after only three cycles of treatment, despite the high expression of PD-L1. In contrast, 8/11 patients with a low-intermediate interstitial expression of Gal-1 had an excellent response to treatment, whereas in the group with high interstitial expression of Gal-1, the response rate was drastically lower (5/15 patients). Conclusions: The expression of interstitial Gal-1 protein and intratumoral Gal-3 protein appear to be a good candidates as predictive markers of response to immunotherapy.