Dr Pereira looked at the distribution and frequency of three different types (genotypes) of the -765G>C COX2 polymorphism: the GG, GC and CC genotypes. An individual genotype is composed of two distinct parts, the inherited sequences from the maternal and paternal genomes. Therefore, for every genotype, there are two copies of the sequence and these copies are called alleles. Alleles may be identical or different.
Dr Pereira explained: The C and G are alleles that can be inherited, one from each parent. As everyone carries two alleles, their genotypes could be a CC, GC or GG genotype. The G allele is the most common, while the CC genotype is rare; therefore, it is usual to pool the GC and CC genotypes together and we call people with these genotypes C allele carriers.
Our results demonstrated that C allele carriers had a nearly two-fold (1.8) increased risk of developing ovarian cancer. This was even more evident when we stratified our analysis into two groups based on the average age of the patients; the women aged 53 or under had a nearly three-fold (2.8) increased risk of developing ovarian cancer.
She said the polymorphism could enhance the expression of the COX2 gene, thereby inhibiting apoptosis (programmed cell death) and promoting tumour proliferation, metastasis and angiogenesis (the formation of new blood vessels needed to supply a growing tumour). The reason why the same effect was not observed in cervical cancer was probably due to the different causes of the two cancers.
The biological mechanism involved in the carcinogenesis of different organs is not always similar. In the case of cervical cancer we know that the trigger mechanism is an oncogenic virus, HPV (human papillomavirus) and that in ovarian cancer, although not as clearly understood, inflammation and hormonal regulation are cr
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