FBLN1 and neoplasm: Furthermore, the ratio of the 50 kDa fragment to the mature fibulin-1 polypeptide correlated with the level of oestrogen receptor α (Spearman correlation coefficient, rs=0.49, P<0.003, n=36) and progesterone receptor (rs=0.43, P=0.008, n=36) expression in the tumour specimens.