EGFR and colorectal carcinoma: Finally, it was discovered that a drug-resistance pathway (EGFR tyrosine kinase inhibitor resistance) was enriched for both types of targeted genes and that CRC cell lines with low expression of PIK3R1 (targeted by exosome miR-23b-3p/miR-221-3p) exhibited resistance to the EGFR-targeted drug lapatinib.