There was also a significant decrease in mammary tumour-free survival in Mmtv-Ccl2 mice compared to control mice (p = 0.025); mean latency (mean ± SD) was 12.7 ± 1.0 weeks in Mmtv-Ccl2 mice, and 16.7 ± 1.4 weeks in control mice. The gene discussed is CCL2; the disease is breast cancer.