Haptoglobin phenotype and epithelial ovarian cancer

Haptoglobin (H) is a glycoprotein that regulates the immune response. Serum haptoglobin levels are significantly higher in patients with advanced epithelial ovarian cancer (EOC) with poor survival. Different isoforms of haptoglobin have been found in the serum of patients with EOC. We studied the genetic susceptibility and outcome of patients with EOC correlated to H phenotypes.

Analyses of the H phenotypes were performed on sera from patients stored at -70°C. A modified method based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of sera was used, followed by western blotting.

Seventy-nine consecutive patients with EOC and 63 healthy women were enrolled. Their mean (± S.D.) age was 58.9 ± 12.46 years. Overall survival was 66 months (95% confidence interval=37.7-94.2). Similar distribution of haptoglobin phenotypes was observed in EOC and in healthy women. No significant correlation was found between haptoglobin phenotype, overall survival and time-to-progression. Fewer G3 tumors were found in patients with H2-2 compared with those with H1-2 (84.2% and 90.6%, respectively, p<0.04). No significant correlation was found between H phenotype and tumor markers or number of relapses.

Although ours is a preliminary study based on a small population with scant significant findings, we hypothesize that patients with EOC with haptoglobin 2-2, might have a better prognosis because they present fewer G3 tumors and they may present a stronger immune response than patients with 1-1 and 1-2 phenotypes. Larger studies should be performed to assess the predictive value of haptoglobin phenotype in patients with EOC.