PTK2 and cancer: In the training set samples, we compared the 21 anoikis-related gene expression between CRC patients and normal adjacent cancers and found that the expression levels of CEACAM6, CHEK2, E2F1, IKBKG, NOTCH1, PTK2, PTRH2, SRC, STK11, and TSC2 were higher in cancerous tissues than they were in normal adjacent tissues (Figure 1A).