Clinical relevance of telomerase polymorphism for breast cancer: A systematic review

To perform a systematic review to explore the clinical relevance of hTERT polymorphisms for breast cancer (BC).

Twenty-nine polymorphic regions were evaluated after comprehensive searching of 1236 articles, and selection of 9 publications (total of 12986 cases and 16758 controls).

About the influence of hTERT variants in BC risk, 3 studies showed that the variant rs2736098 was associated with increasing risk. The variants rs10069690 and rs2853676 were also described as risk factors for BC. Only one variant rs2736100 presented as risk factor for BC. MNS16A genotype influenced the risk of BC in an Iranian, but not in the Greek and American populations. The associations of 5 hTERT variants with expression of hormone receptors were also evaluated in some studies. One study showed that the variant rs10069690 was associated to the estrogen receptor (ER)-negative and triple negative subtype, but other authors did not find the same results. In addition, the association of rs273618 with ER-/progesterone receptor (PR)+ cases, and rs10069690, rs2735940, rs4246742 and rs2736100 with both negative receptors were described. After data reanalyses, we found that the variant rs2735940 and rs2736100 were associated with ER-/PR- cases among patients with BC. Also, the variant rs2736100 was associated with ER+/PR+ cases and the variant rs2736118 was associated to ER+/PR+ and ER-/PR+ cases.

The associations between hTERT variants and BC risk and outcomes could be useful since a polymorphism can be identified before the diagnosis, but the heterogeneity of data and analyses found in different studies lead to many controversies.