Breast cancer‐linked lncRNA u‐Eleanor is upregulated in breast of healthy women with lack or short duration of breastfeeding

AbstractRecently, it has been revealed that estrogen‐related reproductive factors are linked with some early gene expression lesions associated with malignancy in clinically healthy breasts. Accordingly, the aim of the current study was to evaluate the association of expression levels of estrogen‐related long noncoding RNAs (lncRNAs) upstream Eleanor (u‐Eleanor) and HOX antisense intergenic RNA (HOTAIR) with the different patterns of reproductive factors in breast tissue of healthy women. The subjects of this study were 98 cancer‐free women who had undergone cosmetic mammoplasty. The expression levels of u‐Eleanor and HOTAIR were measured using quantitative real‐time polymerase chain reaction. The results of the current study showed that the women without a history of breastfeeding had a high‐level expression of u‐Eleanor compared with the women with a breastfeeding duration greater than 6 to 24 months (P = 0.03) as well as the women with a breastfeeding duration of more than 24 months (P = 0.005). Furthermore, a higher expression of u‐Eleanor was found in the women with a short breastfeeding duration for 1 to 6 months than that in the women with a breastfeeding duration of greater than 24 months (P = 0.02). In the same way, the results of correlation test (r = −0.258; P = 0.036) and multivariate regression model (β = −0.321; P = 0.023) are indicative of a significant relationship of elevated expression of u‐Eleanor with decreasing breastfeeding duration in the women. These findings could be important to identify the molecular mechanisms behind the relationship between a lack or short duration of the breastfeeding and the risk of breast cancer, which has previously been reported by epidemiological studies.