Ethnic variation in the HER-2 codon 655 genetic polymorphism previously associated with breast cancer.
HER-2, a protooncogene located on chromosome 17q21, encodes a transmembrane glycoprotein (p185) with tyrosine kinase activity. Alterations of the HER-2 gene have been implicated in the carcinogenesis and prognosis of breast cancer and other solid tumors. It is also a cancer-therapeutic target for antibody-based therapy against the HER-2 protein. A single-nucleotide polymorphism (SNP) at codon 655, resulting in a G-to-A transition (Ile655Val) in the transmembrane domain-coding region of this gene has been associated with an increased risk of breast cancer, particularly among younger women. To understand the importance of this finding throughout the world, we evaluated this polymorphism in Ghanaian, Kenyan, Sudanese, Caucasian, African-American, Saudi, and Filipino subjects using a polymerase chain reaction-restriction fragment length polymorphism assay. The frequency of the Val allele, which is associated with increased breast cancer risk, was highly variable between populations (0%-24%). Continental African populations had a lower frequency of the Val allele than did Saudi, Chinese, Filipino, Caucasian, and African-American subjects. The data suggest that this SNP has variable frequency in different ethnic groups. The findings in this study correspond with the lower incidence and lower risk of breast cancer in African women compared with Caucasian and African-American women.
Ameyaw
Margaret-Mary
MM
Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110-1093, USA.
Tayeb
Mohammed
M
Thornton
Nadia
N
Folayan
Gbolshan
G
Tariq
Mohammed
M
Mobarek
Abeer
A
Evans
David A
DA
Ofori-Adjei
David
D
McLead
Howard L
HL
D000328:Adult; D019943:Amino Acid Substitution; D044383:Black People; D001943:Breast Neoplasms / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D018734:Genes, erbB-2; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D044465:White People; D001741:Black or African American
D018719:Erb-b2 Receptor Tyrosine Kinases