Haptoglobin phenotype and risk of cervical neoplasia: a case-control study.
BACKGROUND
Haptoglobin is an acute-phase glycoprotein that influences host response to infections and tumours. The haptoglobin locus is polymorphic with 2 classes of alleles (Hp(1) and Hp(2)) yielding 3 phenotypes: Hp1-1, Hp2-2, and Hp2-1 with structurally and functionally distinct protein products, suggesting that haptoglobin polymorphism may influence susceptibility to infections and cancers.


METHODS
We examined the relation between haptoglobin phenotype and high-grade cervical intraepithelial neoplasia (CIN) in a hospital-based case-control study. Cases (n = 307) were women with biopsy-confirmed CIN-2 or CIN-3. Controls (n = 358) were a random sample of women with normal cytology. The PGMY polymerase chain reaction and reverse line blot methods were used for HPV detection and genotyping. Haptoglobin phenotype was determined by polyacrylamide gel electrophoresis.


RESULTS
Among controls, phenotype distribution corresponded to allele frequencies of 0.39 for Hp(1) and 0.61 for Hp(2) with no significant deviation from the Hardy-Weinberg equilibrium (p=0.66). With all women included in the analysis, the Hp1-1 phenotype was associated with increased risk of CIN (OR contrasting Hp1-1 vs. Hp2-2 = 1.0; 95% CI: 0.6-1.5). However, in analyses restricted to HPV-positive participants, the Hp1-1 phenotype was associated with 2.7-fold (95% CI: 1.0-7.2) higher risk of CIN.


CONCLUSIONS
If confirmed, these findings indicate an increased risk of CIN among women with the Hp1-1 phenotype.
Mahmud
Salaheddin M
SM
Division of Cancer Epidemiology, McGill University, Montreal, Canada H2W 1S6.
Koushik
Anita
A
Duarte-Franco
Eliane
E
Costa
Joana
J
Fontes
Gabriela
G
Bicho
Manuel
M
Coutlée
François
F
Franco
Eduardo L
EL
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006242:Haptoglobins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D010641:Phenotype; D012307:Risk Factors; D002583:Uterine Cervical Neoplasms / Q000145:classification / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism*
C485359:HP protein, human; D006242:Haptoglobins