DPYD and colorectal carcinoma: Dihydropyrimidine dehydrogenase (DPYD) plays the dominant role in 5‐FU and capecitabine degradation, and reduced enzyme activity leads to toxicity resulting from toxic metabolite accumulation.13, 14 Large‐scale meta‐analyses have highlighted the importance of DPYD germline polymorphisms in causing toxicities in CRC clinical studies.