EGFR and colorectal carcinoma: The uncertain benefit of anti-EGFR agents in SBA, as well as the differential benefit seen with this therapy in left-sided versus right-sided CRC, has been hypothesized to be related to the embryological and anatomic development of the gastrointestinal tract—the midgut ultimately develops into much of the small intestine as well as the proximal colon, while the more distal, left-sided colon is derived from the hindgut.