[HOTAIR rs920778 single nucleotide polymorphism is associated with breast cancer susceptibility and HER2-targeted...

To investigate the association of HOTAIR gene rs920778 single nucleotide polymorphism (SNP) with breast cancer susceptibility and response to HER2-targeted therapy in a Chinese population.

TaqMan probe-based real-time quantitative PCR was used for genotyping of the rs920778 locus (chr12:54,376,218) in peripheral blood genomic DNA from 287 breast cancer patients and 260 healthy individuals from northern Anhui Province. The genotype (GG, GT and TT) and allele (G/T) distribution frequencies were compared between the two groups to evaluate their association with breast cancer risk. Multivariate logistic regression analysis was conducted to assess the relationship between SNP at this locus and aggressive clinicopathological features (including tumor size, lymph node metastasis, ER/PR/HER2 status, and molecular subtypes) of breast cancer. For the HER2-positive subgroup, the association between rs920778 genotype and responses to dual-targeted therapy (trastuzumab [6 mg/kg q3w]+pertuzumab [420 mg q3w] + docetaxel [75 mg/m²]) was analyzed. The primary endpoints included pathological complete response rate (pCR), objective response rate (ORR), and progression-free survival (PFS).

The TT genotype of rs920778 was associated with a significantly increased breast cancer susceptibility (OR=1.54, 95% CI: 1.09-2.19; P=0.017), an advanced tumor stage (P<0.001), lymph node metastasis (P<0.001), and the triple-negative subtype (P<0.001). In HER2-positive patients, TT genotype carriers had a markedly reduced objective response rate to dual HER2-targeted therapy (33.3% vs 89.3%, P=0.001) and a lower pathological complete response rate after neoadjuvant therapy (P=0.018).

The TT genotype of HOTAIR rs920778 serves as an independent risk factor for breast cancer susceptibility and aggressive progression in Chinese population and may predict the resistance to HER2-targeted therapies, suggesting its potential as a prognostic biomarker for precision oncology.