Low expression of calpain-9 was significantly associated with a number of clinicopathological factors, including; patients over 40 years (χ2 = 5.04, d.f. = 1, P = 0.025), smaller tumour size (χ2 = 10.67, d.f. = 1, P = 0.001), smaller tumour stage (χ2 = 9.34, d.f. = 2, P = 0.009), more favourable Nottingham prognostic index (NPI) values (χ2 = 12.96, d.f. = 2, P = 0.002), and ER positive tumours (χ2 = 6.09, d.f. = 1, P = 0.014). The gene discussed is CAPN9; the disease is neoplasm.