Yao et al. [45], in a molecular characterization of 79 CRC PDX models by whole-exome and RNA sequencing as well as SNP6.0 analysis, showed that key genetic mutations and their frequencies, such as APC (75.9%), p53 (70.9%), KRAS (55.7%), NRAS (5.1%), BRAF (15.2%), PIK3CA (26.6%), PTEN (12.7%), PIK3R1 (6.3%), and CTNNBI (3.8%), were consistent with the data reported for human CRC tumors [45,46]. The gene discussed is PTEN; the disease is colorectal carcinoma.