ESR1 Mutation Analysis, Next-Generation Sequencing, Tumor

Clinical Use

Use

This test assists in the clinical management of patients with metastatic breast cancer by identifying tumors with evolving resistance to endocrine therapy. It helps in stratifying the prognosis of metastatic breast cancer. The test evaluates somatic mutations within the ESR1 gene to provide insights into the potential mechanisms leading to resistance against endocrine treatments such as selective estrogen receptor modulators and degraders, and aromatase inhibitors. By identifying mutations in the ligand-binding domain of ESR1, the assay aids in determining patient eligibility for targeted therapies like elacestrant (Orserdu), which is indicated for specific patient groups with ESR1 mutations.

Special Instructions

Not provided.

Limitations

The test cannot differentiate between somatic and germline alterations. A negative result does not preclude the presence of a variant that may be below detection limits or is unaddressed by this assay. Multiexon deletions and duplications are not detected, nor are genomic copy number variants. Analytical sensitivity for sequence-reportable alterations requires at least a 5% mutant allele frequency. Reliable results depend on proper specimen collection and processing, avoiding decalcified tissues. Additional testing may be required to clarify results or if there's a potential hereditary risk.

Test Details

New York Approved