CAST and neoplasm: Tumours were then recategorised according to expression of any two of calpain-1, -2, and -4, and calpastatin into four groups each time; for example, using calpain-1 and -2 expression the recategorised groups are: tumour with low expression of both calpain-1 and -2; tumour with high expression of both calpain-1 and -2; tumour with low calpain-1 and high calpain-2 expression; tumour with high calpain-1 and low calpain -2 expression.