CXCL1 and cancer: The upregulation of gene and protein expression of caspases 3 and 7, as shown here, might be an alternative route to induce apoptosis, whereby the classical initiation of apoptosis is bypassed: it is possible that the exercise-induced factors CXCL1, IL10 and CCL4 enhance cancer cell apoptosis by increasing the availability of caspase 3 and 7.