Serum samples with episodes of tumour control (n=112) showed an increase of matrix metalloproteinase-2 (MMP-2) (P⩽0.01) and a decrease of tissue inhibitor of MMPs (TIMP-1) levels (P⩽0.01), while serum samples with episodes of tumour progression displayed the reverse pattern (P⩽0.01 and P⩽0.05, resp). Here, MMP2 is linked to neoplasm.