Abstract 408: Reduction of tumor-infiltrating B cells linked to recurrence of NSCLC tumors

Introduction: Lung cancer is the leading cause of cancer related mortality worldwide. Non-small cell lung cancer (NSCLC), accounting for approximately 80-85% of all lung cancer cases, is characterized by a poor response to chemotherapy and a low survival rate. Early stage NSCLC patients are typically treated with complete surgical resection of the tumor, but nevertheless 30-50% of these patients end up developing recurrence within 5 years of surgery. While the presence of tumor-infiltrating lymphocytes (TILs) has been shown to be significantly correlated with a positive clinical prognosis in multiple types of cancer the role of tumor-infiltrating B cells (TIBs) remains more controversial. Experimental Procedures: To perform a comprehensive immunoprofiling of NSCLC FFPE tumor samples we used MultiOmyx™, a proprietary immunofluorescent multiplexing assay. Using a 15-marker panel we have analyzed the proportion of T cell subtypes, B cells, Granulocytes, M1/M2-type tumor-associated macrophages, as well as the expression of PD-1, PD-L1, LAG-3, TIM-3, ICOS, and OX40 in 12 samples from patients with early stage (stage I-II) NSCLC (6 non-recurrent and 6 recurrent). Results: Using the MultiOmyx image analysis suite based on NeoGenomics' proprietary deep-learning algorithms, we compared the number and overall density of immune cell populations between non-recurrent and recurrent NSCLC samples and found recurrent samples to have a highly significant decrease in B cells (166.8 cells/mm2 to 26.2 cells/mm2; p-value 0.006). In addition to a decrease in the overall density of B cells, we also observed a decrease in the tumor-infiltration rate, measured as the % of cells found inside the tumor area versus in the stroma of the tumor samples. This demonstrates that not only are there fewer B cells in the recurrent samples, but the B cells present are also less likely to infiltrate into the tumor area. While research on tumor immunity has been highly focused on T cells, the specific role of B cells in this area has been somewhat overlooked. While the release of antibodies and interleukin-10 might be involved in TIB-mediated tumor immunity, interactions between TIBs and TILs as well as the PD-1/PD-L1 cascade has been documented more recently. Indeed, in our study we did observe a significant positive correlation between the densities of B cells and cytotoxic lymphocytes, as well as B cells and PD-L1, although interestingly this was only observed in the recurrent group of patie