Purpose: Kallikrein is considered as a mediator of tumorigenesis. Various studies examing the relationship between high kallikrein expressions with the clinical outcome in patients with ovarian cancer have yielded controversial conclusions.
Methods: We conducted a meta-analysis of 10 studies (N=1478) that evaluated the relationship between positive kallikrein expression and overall survival and progression-free survival (PFS). Data were analyzed with random effect and combined hazard ratios (HR) by STATA software.
Results: Positive kallikrein expression was significantly associated with worse OS (HR for OS was 2.01, 95%CI: 1.68-2.34, p<0.05). Subgroup analysis showed that kallikrein detected by RT-PCR was related with OS (HR=2.51, 95%CI: 2.16-2.86, p<0.05), as well as by nonY-PCR methods (HR=1.6, 95%CI: 1.08-2.12, p<0.05). The heterogeneity among studies was significant (I2-91%, p=0.000). Begg's and Egger's test showed p=0.813 and p=0.938, respectively. The estimated HR for PFS was 1.83, 95%CI: 1.51-2.14, p<0.05). The heterogeneity among studies was significant (I2=88.9%, p=0.000). Begg's and Egger's test showed p=0.93 and p=0.88, respectively. Furthermore, confunnel plot (contour-enhanced funnel plot) was undertaken which also showed absence of publication bias for both OS and PFS.
Conclusion: Although the presence of some modest bias cannot be avoided, positive kallikrein expression seems to be associated with worse OS and PFS in patients with ovarian cancer.