Radiation-induced changes in gene expression in rectal cancer specimens

TL;DR

This paper reviews how radiotherapy affects gene expression in rectal cancer, highlighting increased immune activity.

Contribution

The study systematically reviews transcriptomic changes in rectal cancer due to radiotherapy, emphasizing immune-related gene upregulation.

Findings

Radiotherapy in rectal cancer is associated with broad upregulation of immune activity at the transcriptome level.

Variation in study design and sampling timing limits direct comparison across studies.

Most post-treatment gene expression data was collected at the time of surgical resection.

Abstract

The standard-of-care for locally advanced rectal cancer is radiotherapy-based neoadjuvant therapy followed by surgical resection. This article reviews the evidence of molecular changes at the transcriptome level induced through radiotherapy in rectal cancer.

The PubMed search “(radiation OR radiotherapy) cancer (transcriptome OR “gene expression”) rectal” was used. The studies taken forward utilised gene-expression data on both pre-treatment and post-treatment rectal adenocarcinoma biospecimens from patients treated with RT-based neoadjuvant strategies.

Twelve publications met the review criteria. There was variation in approaches in terms of design, patient population, cohort size, timing of the post-radiotherapy sampling and method of measuring gene expression. Most of the post-treatment biospecimen retrievals were at resection. The literature indicates a broad upregulation of immune activity through radiotherapy using gene-expression data.

Future studies would benefit from standardised prospective approaches to sampling to enable the inclusion of timepoints relevant to the tumour and immune response.

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