It was also noteworthy that out of the 17 metastatic squamous cell cancers whose sites of origin included colon (1 of 17), esophagus (3), larynx (1), lung (3), nasopharynx (4), penis (1), and unknown tissues (4), 15 were CXCR4+ (Table 3). This evidence concerns the gene CXCR4 and squamous cell carcinoma.