Collectively, these data suggest that elevated expression of CLDN1, PIK3CA, SLC6A6, TMEM-43, ASAP-1, and CD44, and decreased expression of CLDN7 in CRC are associated with a poor response to FOLFOX chemotherapy, thus supporting our rationale for utilizing this novel CLDN-associated molecular signature to identify high-risk patients. Here, PIK3CA is linked to colorectal carcinoma.