The Association Between Cancer Of The Breast And The Abo And Rhesus D Antigen Phenotypes In Lagos, Nigeria; A Case-Control Study
AbstractObjective: To determine whether inheritance of ABO and Rhesus D antigen phenotypes constitute a risk factor for development of cancer of the breast.
Design: A case-control study.
Setting: Patients with histologically diagnosed cancer of the breast referred to Radiotherapy department of the Lagos University Teaching Hospital over a six-month period were included in the study (cases). Healthy blood donors at the Donors Clinic of the hospital over the same period of time were also studied (Control A). Women attending family planning clinic were also studied and referred to as Control B.
Materials & Methods: Routine ABO and Rhesus D-phenotyping was carried out on washed red cell specimens of all cases and controls. The odds that cancer of the breast was due to presence of a given phenotype were determined (odds of cases). The odds that the given phenotype is present in the normal population without cancer of breast was also determined (odds of control). The Odds Ratio (OR) given by odds of cases/odds of control served as an estimate of the Relative Risk (RR) that the given phenotype is associated with the cancer of the breast.
Result: 107 cases, 2.243 controls A and 122 controls B were studied. Of the cases, only one was a male, the others were females. Their ages ranged between 24 and 85 years with a median of 45 years. The controls A were all males with ages ranging between 22 and 55 years. Controls B were females with ages ranging between 21 and 47 years.
A,B,O, AB, Rhesus D positive and Rhesus D negative phenotype distribution amongst the cases, controls. A and B were 28,22,54,3,97 and 10,589,440,1143,71,2142 and 101,27,25,70,.0,117 and 5 respectively.
Of all the phenotypes, only the inheritance of Rhesus D antigen gave a relative risk (RR) significantly below unity. RR=0.45. Standard error=0.76 and p. <0.05 when cases were compared with controls A. RR=0.41,SE=0.56 and P>0.05 when cases were compared with control B.
Conclusion: Negative association was established between inheritance of Rhesus D antigen and the development of cancer of the breast. Rhesus D antigen phenotype may be protective against cancer of the breast.
KEYWORDS; ABO Blood group, Rhesus D blood group, relative risk, attributable risk, Absolute risk. Carcinoma of the Breast.
Nigerian Journal of Clinical Practice Vol.5(2) 2002: 81-86