PTK2 and cancer: Our study demonstrated that CPNE8 promotes tumor progression via regulation of focal adhesion, and these effects can be rescued by focal adhesion kinase (FAK) inhibitor GSK2256098 or knockdown of FAK. In addition, CPNE8 was correlated significantly with the infiltration of cancer-associated fibroblasts and immune cells, as demonstrated by various algorithms, and high CPNE8 expression predicted poor efficacy of immune checkpoint therapy.