Novel intronic RHD variants identified in serologically D-negative blood donors.

BACKGROUND: Blood group genotyping is used to predict RhD phenotype in transfusion and obstetric medicine. Prediction of antigen D is based on molecular techniques which targets most common RHD-specific polymorphism. However, inactive RHD variants can suggest false-positive RhD phenotype. Their types and frequencies vary among ethnicities. Our study aimed to identify RHD variants among Moroccan blood donors who are serologically D negative. STUDY DESIGN AND METHODS: DNA from 53 blood donors who are serologically D negative RhC and/or RhE positive were screened for RHD exon 10 by PCR-SSP. RHD-positive samples were further tested by multiplex PCR covering exons 3, 4, 5, 6, 7 and 9 and then sequenced by targeted next-generation sequencing method. Mutations' impact on mRNA splicing was predicted using alamut software version 2·0. RESULTS: PCR-SSP revealed 9 of 53 (16·9%) RHD-positive samples. Five of nine samples were positive for all tested exons, two of nine were positive for exon 9, and two of nine were undetermined. Sequencing revealed four novel RHD variants based on six mutations in introns 1, 3, 5 and 6. In silico analysis revealed aberrant splicing of three mutations (RHD c.487-1024delG, RHD c.487-256T>G and RHD c.940-187_940-188del), while three other mutations (RHD c.149-682C>A, RHD c.802-37delA and RHD c.939 + 1151dup) had no effect on splicing compared to wild type. CONCLUSIONS: All identified RHD variants contain at least one mutation that probably affects splicing to generate D-negative phenotype. Hence, ethnic RhD antigen background must be considered when developing transfusion and obstetric strategies.

Immunohistochemical and genetic exploration of incompatible A blood group antigen expression in invasive micropapillary breast carcinoma: A case report.

INTRODUCTION: Invasive Micropapillary Carcinoma (IMPC) of the breast is a relatively rare subtype of invasive ductal carcinoma and represents the most inherently aggressive form. Expression of incompatible blood group A antigen in cancer of type O patients has been reported in several types of cancer, however, the biosynthetic mechanism and the genetic basis remain unclear until today. The aim of the present case report study was to evaluate the expression of incompatible blood group A antigen and to identify the genetic basis of this expression in IMPC of the breast. MATERIAL AND METHODS: One patient blood group O with Invasive Micropapillary Carcinoma was screened at Pathology Department of University Hospital CHU Ibn Rochd, Casablanca. ABH antigens expression was assessed by immunohistochemistry. ABO genotyping was performed by allele specific primers PCR-ASP and Exon 6 of ABO gene was sequenced with Sanger method. RESULTS: H antigen was expressed in endothelial and epithelial cells of normal tissue. However, H antigen expression was lost in both invasive micropapillary carcinomas. A antigen was expressed in IMPC with approximately 80% of positive cells. Tumor DNA was genotyped as heterozygous A/O. In normal DNA, we identified a single frameshift deletion c.320delA p.(Glu107Glyfs*12), which is removed from tumor DNA. CONCLUSION: Our findings suggest that incompatible A antigen expression in IMPC is due to glycosyltransferase A encoded by an A allele which is derived from O allele with a deletion at the position 320.

ABO blood groups in relation to breast carcinoma incidence and associated prognostic factors in Moroccan women.

The association between blood groups ABO and different types of diseases was established in several previous studies. Our aim was to seek the possible association between the ABO blood group and breast cancer-associated prognostic factors. The Chi-squared analytic test was used to compare phenotypic ABO distribution among Moroccan blood donors and 442 cases of women suffering from breast carcinoma with archived files in Maternity Ward of University Hospital C.H.U Ibn Rochd between 2008 and 2011. High incidence of breast carcinoma was observed in blood type B patients (p < 0.05). Blood type B was associated with breast carcinomas overexpressing human epidermal growth factor receptor HER2 (p < 0.05) and high risk of cancer at age over 70 years (p < 0.001). Blood type A was associated with high risk of cancer among women younger than 35 years old. Blood type A and AB were associated with high incidence of lymph node metastasis (p < 0.05). Multivariate analysis has shown correlation between O blood type and estrogen receptor-positive tumor. Patients with blood group A, B, and AB were more likely to develop aggressive breast carcinoma. Further follow-up studies are necessary to clarify the role of ABH antigens in the progression of breast carcinoma.