Overview

A 73-gene lung cancer panel is a next-generation sequencing (NGS) product designed to read many cancer-relevant genes from one tumor sample. Its value comes not from the gene count alone but from a carefully controlled laboratory workflow that turns fragmented DNA into a reportable list of variants. This article explains the mechanism of the panel, step by step, for labs and buyers evaluating such a test.

How the 73-Gene NGS Panel Is Built

The workflow begins with nucleic-acid extraction from the tumor specimen, followed by quality checks on quantity and fragmentation. Targeted regions across the 73 genes are then captured — most often by hybridization-based enrichment or by amplicon-based methods — and adapted into a sequencing library. Enrichment choice affects how well low-frequency variants and gene fusions are recovered, so the capture design is matched to the panel's clinical intent.

After sequencing, raw reads are aligned to a reference genome and variants are called. The pipeline identifies single-nucleotide variants, small insertions or deletions, copy-number changes, and selected rearrangements. A 73-gene lung panel is also typically equipped to estimate tumor mutational burden and to flag actionable alterations recommended by guidelines, which raises its utility beyond a simple mutation list.

Turning Sequence Data into Guidance

Called variants pass through filters for quality, allele fraction, and population frequency, then are annotated with clinical knowledge bases and classified by pathogenicity. The final report presents the alterations most likely to influence therapy, trials, or prognosis, with the supporting evidence summarized for the oncologist.

For distributors, the differentiator is reproducibility: a panel is only as good as its validated limit of detection and its bioinformatics transparency, so those specifications should be front and center in any product comparison.

FAQ

Q: Does a 73-gene panel detect fusions as well as point mutations?
A: Yes, when the capture design and pipeline support rearrangement calling, which most lung panels build in for drivers like ALK and ROS1.

Q: How is tumor mutational burden measured on the panel?
A: TMB is estimated from the count of somatic variants across the sequenced region, using a defined algorithm.

Q: What sample quality is needed?
A: A minimum tumor content and intact DNA are required; low-quality samples may need extraction re-work before library prep.

Q: Why choose 73 genes instead of a smaller panel?
A: A broader gene set captures more trial options and resistance markers while still fitting a single NGS workflow.