Conclusion
Our data provide evidence that PCLO is differentially expressed in GC and might delay tumour progression.
Methods
Tumour samples (whole tissue sections) obtained from 466 patients resected for therapy-naive GC were stained with an anti-PCLO antibody. The histoscore for tumour cells and the presence of immunostaining of stromal cells and tumour vessels was documented for each case. An algorithm for PCLO immunopositivity was formed and correlated with clinicopathological patient characteristics.
Results
175 GCs were classified as PCLO positive within tumour cells, and 291 as negative. Stromal cells were positive for PCLO in 106 cases and tumour vessels in 84. PCLO-positive GCs more often showed an intestinal phenotype, a lower T category and were more commonly associated with Helicobacter pylori infection. A separate analysis of PCLO expression in intestinal and diffuse type GCs, respectively, showed no significant correlations. Patients with PCLO negative/low tumour cells showed a shortened overall (14.0 ± 1.4 vs. 16.0 ± 1.8 months) and tumour-specific survival (15.0 ± 1.6 months vs. 17.9 ± 3.6). Comparison of PCLOs genotype with its phenotype in 48 tumour samples obtained from nine cases showed no direct correlations with missense mutations.