The incubation of differentiated myotubes with sera from cancer patients led to a decrease in both LC3 expression and p62 expression (LC3 = 1.54 ± 0.76 for the control group vs. 0.94 ± 0.14 for the cancer group, p = 0.01; p62 = 0.90 ± 0.26 for the control group vs. 0.54 ± 0.23 for the cancer group, p = 0.008). This evidence concerns the gene MAP1LC3A and cancer.