Composite biomarkers defined by multiparametric immunofluorescence analysis identify ALK-positive adenocarcinoma as a potential target for immunotherapy.

Anaplastic lymphoma kinase (ALK) inhibitors have been successfully developed for non-small cell lung carcinoma (NSCLC) displaying chromosomal rearrangements of the gene, but unfortunately resistance invariably occurs. Blockade of the PD-1-PD-L1/2 inhibitory pathway constitutes a breakthrough for the treatment of NSCLC. Some predictive biomarkers of clinical response to this therapy are starting to emerge, such as PD-L1 expression by tumor/stromal cells and infiltration by CD8 T cells expressing PD-1. To more effectively integrate all of these potential biomarkers of clinical response to immunotherapy, we have developed a multiparametric immunofluorescence technique with automated immune cell counting to comprehensively analyze the tumor microenvironment of -positive adenocarcinoma (ADC). When analyzed as either a continuous or a dichotomous variable, the mean number of tumor cells expressing PD-L1 ( = 0.012) and the percentage of tumor cells expressing PD-L1 were higher in -positive ADC than in ADC or WT (non--mutated and non--mutated) NSCLC. A very strong correlation between PD-L1 expression on tumor cells and intratumoral infiltration by CD8 T cells was observed, suggesting that an adaptive mechanism may partly regulate this expression. A higher frequency of tumors combining positive PD-L1 expression and infiltration by intratumoral CD8 T cells or PD-1CD8 T cells was also observed in -positive lung cancer patients compared with -mutated ( = 0.03) or WT patients ( = 0.012). These results strongly suggest that a subgroup of -positive lung cancer patients may constitute good candidates for anti-PD-1/-PD-L1 therapies.