Expression of PC1 in normal and unaffected liver compared to colorectal (CRC) liver metastases. A. Quantification of PC1 mRNA expression respectively, in 3 normal (N), 14 tumor (T) and 14 unaffected (U) liver samples. Quantification was obtained by the ratio of the optical density of PC1 PCR amplification products over GAPDH. Standard error of mean (SEM) is indicated. Asterisk indicates a statistically significant difference (P < 0.04). B. Schematic representation of PC1 structure. The antigenic region against which the antibody was raised is mentioned (YAb). Cleavage sites are indicated (arrows). C. PC1 cleavage profile in normal (N1-N3, top panel), unaffected (U1-U2) and tumor (T1-T2, bottom panel) samples. Normal liver samples (N1-N3) derived from three different organ donors. T1/U1 and T2/U2 came from two independent patients. PC1 immunoblotting was done on a total of 3 normal, 14 metastasis and 14 unaffected liver samples, and was repeated three times. D. Relative amounts of total PC1 (C, left panel) protein, in tumor (T), unaffected (U) and normal liver (N), expressed as a ratio over normal liver samples. Ratios of p84/p66 PC1 isoforms (C, right panel) in the same samples are calculated. SEM is indicated. Simple and double asterisks indicate statistically significant differences (P < 0.05).