# Characterization of Small Genetic Variants in Breast Cancer Cell Line Under Tamoxifen Therapy: Alterations of Small Genetic Variants Under Tamoxifen Therapy

## TL;DR

This study examines how tamoxifen affects genetic variants in breast cancer cells and finds no clear link between variant changes and treatment effectiveness.

## Contribution

The study investigates the role of genetic variant alterations under tamoxifen therapy in breast cancer cells using RNA-seq data and gene ontology analysis.

## Key findings

- Over 5.8 million genetic variants were identified, with 67 differential variants between treated and untreated samples.
- Differential variants were associated with tumor suppressors and oncogenes like IL6ST, GEN1, and DDX11.
- Tamoxifen-induced genetic variant changes do not significantly impact treatment effectiveness.

## Abstract

Tamoxifen (TAM) is an effective hormone therapy in order to reduce the risk of cancer recurrence. According to the available findings, TAM contributes to the alterations of genetic variants background and may have role in the effectiveness of treatments via alteration of the genetic variants. The effects of TAM on genomic features were investigated in current study through discovering genetic variants and finding the answer of the following question: “Is there any association between the alterations of genetic variants under TAM consumption and an effective treatment process?”

Whole-transcriptome (RNA-seq) dataset of four investigations including 10 TAM-treated samples and 9 untreated samples as the control groups were derived from European Bioinformatics Institute (EBI). Using the process of variants calling, the differential genetic variants between and gene ontology enrichment analysis were detected through CLC Genomics Workbench (12).

In current study, almost 5.8 million genetic variants were reported. The outcomes of chi-square test showed that distributions of genetic variants between control and treated samples were significant (P0.05). The genetic variants comparison between the control and TAM-treated samples indicated that there were 67 differential genetic variants. Gene ontology enrichment analysis indicated that differential genetic variants were associated with several tumor suppressors and oncogenes such as IL6ST, GEN1, FNTA. HSPA5, NSMCE2, and DDX11.

Most of the candidate genes with differential genetic variants had dual roles as oncogenes or tumor suppressors. Therefore, it can be claimed that TAM has no significant role in an effective treatment through alteration of the genetic variants. In other words, it cannot be concluded that the TAM therapy-resulted alterations of genetic variants have positive or negative roles in the treatment process.