Clinical development of PD-1/PD-L1 immunotherapy for gastrointestinal cancers: facts and hopes.

Abstract

Gastrointestinal (GI) cancers are among the most deadly malignancies. Whereas serial incremental survival benefits have been made with cytotoxic chemotherapy with metastatic disease, a plateau of achievement has been reached. Applying modern integrative genomic technology, distinct molecular subgroups have been identified in GI cancers. This not only highlighted the heterogeneity in tumours of each primary anatomical site, it also identified novel therapeutic targets in distinct molecular subgroups and might improve the yield of clinical success. Molecular characteristics of tumours and their interaction with tumour microenvironment would further impact on development of combination therapy, including immunotherapy. Currently immune checkpoint blockade attracts the most intense research and the successful integration of these novel agents in GI cancers in the treatment paradigm requires an in-depth understanding of the diverse immune environment of these cancers.