ExaccType ESR1 dPCR Kit

Product Overview

• Detects 11 ESR1 mutations in exons 5, 7, and 8 in a single workflow
• Detects low-frequency ESR1 mutations with demonstrated sensitivity at 0.1% MAF
• Suppresses wild-type signals for selective mutation detection
• Runs on dPCR systems supporting FAM™, ROX, HEX™ and Cy5^®

The ExaccType ESR1 dPCR Kit is a Research Use Only (RUO) digital PCR assay for sensitive detection of 11 mutations in the estrogen receptor alpha gene (ESR1). The assay covers selected variants in exons 5, 7, and 8 and can be used with DNA, including circulating cell-free DNA (cfDNA). Detection at 0.1% mutant allele frequency (MAF) was demonstrated under evaluated study conditions. The ExaccType ESR1 dPCR Kit supports oncology and translational research, including liquid-biopsy studies of low-frequency ESR1 mutations.

Biomarkers

Exon 5: E380Q

Exon 7: S463P

Exon 8: P535H, L536R, L536Q, L536H, L536P, Y537C, Y537S, Y537N, D538G

Scientific Background

ESR1 Gene and Mutations in Research

ESR1 encodes estrogen receptor alpha (ERα), a transcription factor that plays a central role in estrogen signaling and breast cancer biology. Somatic ESR1 mutations are frequently investigated in hormone receptor-positive breast cancer, particularly in studies of tumor evolution, endocrine resistance, and disease progression. Analysis of these variants supports translational oncology, biomarker research, liquid biopsy applications, and investigations of circulating tumor DNA (ctDNA).

Digital PCR-Based ESR1 Analysis

Digital PCR (dPCR) enables highly sensitive detection of low-frequency ESR1 mutations in DNA extracted from tumor tissue and plasma-derived cell-free DNA (cfDNA). The technology provides precise discrimination between wild-type and mutant alleles, supporting applications in assay development, biomarker evaluation, and translational cancer research. The ExaccType ESR1 dPCR Kit detects 11 clinically relevant ESR1 mutations across exons 5, 7, and 8 in a single workflow.

Analytical Performance and Sensitivity

Analytical sensitivity was evaluated using samples contrived with wild-type (WT) and mutant DNA at 0.1% mutant allele frequency (MAF). Six replicates per target were tested across one instrument and two kit lots, with all replicates correctly detected at the evaluated 0.1% MAF level. The table below summarizes the 11 ESR1 mutations detected and the corresponding mutant and wild-type (WT) DNA copy numbers used during assay evaluation*.

Table 1. Analytical sensitivity of the ExaccType ESR1 dPCR Kit for 11 ESR1 mutations.

*Analytical performance data were generated by APIS Assay Technologies Ltd (Manchester, United Kingdom) and adopted for the ExaccType ESR1 dPCR Kit. The ExaccType ESR1 dPCR Kit is manufactured under license of APIS Assay Technologies Ltd for BIOTYPE GmbH.