IFN-α treatment for 20 days (group H) resulted in a significant reduction of tumor weight compared with control group G (2.28 ± 0.63 vs. 3.90 ± 0.80 g, P = 0.003), which suggested that the reduced inhibitory effect of re-initiated IFN treatment was not influenced by the pre-treatment tumor size. This evidence concerns the gene IFNA1 and neoplasm.