MRE11 and ATM Expression Levels Predict Rectal Cancer Survival and Their Association with Radiotherapy Response

<div><p>Background</p><p>Aberrant expression of DNA repair proteins is associated with poor survival in cancer patients. We investigated the combined expression of MRE11 and ATM as a predictive marker of response to radiotherapy in rectal cancer.</p><p>Methods</p><p>MRE11 and ATM expression were examined in tumor samples from 262 rectal cancer patients who underwent surgery for rectal cancer, including a sub-cohort of 54 patients who were treated with neoadjuvant radiotherapy. The relationship between expression of the two-protein panel and tumor regression grade (TRG) was assessed by Mann–Whitney U test and receiver operating characteristics area under curve (ROC-AUC) analysis. The association between expression of the two-protein panel and clinicopathologic variables and survival was examined by Kaplan-Meier methods and Cox regression analysis.</p><p>Results</p><p>A high score for two-protein combined expression in the tumor center (TC) was significantly associated with worse disease-free survival (DFS) (<i>P</i> = 0.035) and overall survival (OS) (<i>P</i> = 0.003) in the whole cohort, and with DFS (<i>P</i> = 0.028) and OS (<i>P</i> = 0.024) in the neoadjuvant subgroup (n = 54). In multivariate analysis, the two-protein combination panel (HR = 2.178, 95% CI 1.115–4.256, <i>P</i> = 0.023) and perineural invasion (HR = 2.183, 95% CI 1.222–3.899, <i>P</i> = 0.008) were significantly associated with DFS. Using ROC-AUC analysis of good versus poor histological tumor response among patients treated preoperatively with radiotherapy, the average ROC-AUC was 0.745 for the combined panel, 0.618 for ATM alone, and 0.711 for MRE11 alone.</p><p>Conclusions</p><p>The MRE11/ATM two-protein panel developed in this study may have clinical value as a predictive marker of tumor response to neoadjuvant radiotherapy, and a prognostic marker for disease-free and overall survival.</p></div

Patient demographics.

BackgroundNext generation sequencing (NGS) is increasingly used in standard clinical practice to identify patients with potentially actionable mutations. Stratification of NGS mutation tiers is currently based on the European Society of Medical Oncology (ESMO) Scale for Clinical Actionability of Molecular Targets (ESCAT[E]) Tier I–V & X. Allele frequency is also increasingly recognised as an important prognostic tool in advanced cancer. The aim of this study was to determine the genomic mutations in metastatic colorectal cancer (CRC) in an Australian multicultural population and their influence on survival outcomes.MethodsNext generation sequencing with the 50-gene panel Oncomine Precision Assay™ was used on 180 CRC tissue samples obtained across six Sydney hospitals between June 2021 and March 2022.ResultsFrom 180 samples, 147 (82%) had at least one gene mutation identified with 68 (38%) having two or more concurrent mutations. Tier I variants included RAS wild-type [EI] in 73 (41%) and BRAF V600E [EIA] in 27 (15%). Non-tier I variants include 2 (1%) ERBB2 amplification [EIIB], 26 (15%) PIK3CA hotspot mutations [EIIIA] and 9 (5%) MET focal amplifications [EIIIA]. NGS testing revealed an additional 22% of cases with Tier II & III mutations. 43% of patients also presented with potentially actionable Tier III & IV mutations. Patients with concurrent TP53 and RAS mutations had significantly reduced overall survival (6.1 months versus 21.1 months, p KRAS allele frequency, as defined by those with over 20% variant allele frequency (VAF), also demonstrated reduced overall survival (12.1 months versus 42.9 months, p = 0.04).ConclusionsIn addition to identifying patients with genomic alterations suitable for clinically proven standard of care therapeutic options, the 50 gene NGS panel has significant potential in identifying potentially actionable non-tier 1 mutations and therefore may become future standard clinical practice.</div

Distribution of concurrent mutations identified by next generation sequencing in colorectal cancer.

Individual patients with concurrent mutations in each column. Tiers 1–3 as outlined by the European Society of Medical Oncology Scale for Clinical Actionability of Molecular Targets.</p

Overall survival of RAS-mutated metastatic colorectal cancer based on allele frequency.

Kaplan-Meier curve comparing KRAS high variant allele frequent as defined by over 20% (yellow) vs KRAS low variant allele frequent as defined by below 20% (blue). Dotted line represents median (12.1 months versus not reached, HR 2.2, 95%CI 1.3–6.7, p = 0.04).</p

Mutations identified using next generation sequencing as stratified by the European society of medical oncology scale for clinical actionability of molecular targets guidelines.

Mutations identified using next generation sequencing as stratified by the European society of medical oncology scale for clinical actionability of molecular targets guidelines.</p

ESMO tiers of mutational actionability.

BackgroundNext generation sequencing (NGS) is increasingly used in standard clinical practice to identify patients with potentially actionable mutations. Stratification of NGS mutation tiers is currently based on the European Society of Medical Oncology (ESMO) Scale for Clinical Actionability of Molecular Targets (ESCAT[E]) Tier I–V & X. Allele frequency is also increasingly recognised as an important prognostic tool in advanced cancer. The aim of this study was to determine the genomic mutations in metastatic colorectal cancer (CRC) in an Australian multicultural population and their influence on survival outcomes.MethodsNext generation sequencing with the 50-gene panel Oncomine Precision Assay™ was used on 180 CRC tissue samples obtained across six Sydney hospitals between June 2021 and March 2022.ResultsFrom 180 samples, 147 (82%) had at least one gene mutation identified with 68 (38%) having two or more concurrent mutations. Tier I variants included RAS wild-type [EI] in 73 (41%) and BRAF V600E [EIA] in 27 (15%). Non-tier I variants include 2 (1%) ERBB2 amplification [EIIB], 26 (15%) PIK3CA hotspot mutations [EIIIA] and 9 (5%) MET focal amplifications [EIIIA]. NGS testing revealed an additional 22% of cases with Tier II & III mutations. 43% of patients also presented with potentially actionable Tier III & IV mutations. Patients with concurrent TP53 and RAS mutations had significantly reduced overall survival (6.1 months versus 21.1 months, p KRAS allele frequency, as defined by those with over 20% variant allele frequency (VAF), also demonstrated reduced overall survival (12.1 months versus 42.9 months, p = 0.04).ConclusionsIn addition to identifying patients with genomic alterations suitable for clinically proven standard of care therapeutic options, the 50 gene NGS panel has significant potential in identifying potentially actionable non-tier 1 mutations and therefore may become future standard clinical practice.</div

S1 Data -

BackgroundNext generation sequencing (NGS) is increasingly used in standard clinical practice to identify patients with potentially actionable mutations. Stratification of NGS mutation tiers is currently based on the European Society of Medical Oncology (ESMO) Scale for Clinical Actionability of Molecular Targets (ESCAT[E]) Tier I–V & X. Allele frequency is also increasingly recognised as an important prognostic tool in advanced cancer. The aim of this study was to determine the genomic mutations in metastatic colorectal cancer (CRC) in an Australian multicultural population and their influence on survival outcomes.MethodsNext generation sequencing with the 50-gene panel Oncomine Precision Assay™ was used on 180 CRC tissue samples obtained across six Sydney hospitals between June 2021 and March 2022.ResultsFrom 180 samples, 147 (82%) had at least one gene mutation identified with 68 (38%) having two or more concurrent mutations. Tier I variants included RAS wild-type [EI] in 73 (41%) and BRAF V600E [EIA] in 27 (15%). Non-tier I variants include 2 (1%) ERBB2 amplification [EIIB], 26 (15%) PIK3CA hotspot mutations [EIIIA] and 9 (5%) MET focal amplifications [EIIIA]. NGS testing revealed an additional 22% of cases with Tier II & III mutations. 43% of patients also presented with potentially actionable Tier III & IV mutations. Patients with concurrent TP53 and RAS mutations had significantly reduced overall survival (6.1 months versus 21.1 months, p KRAS allele frequency, as defined by those with over 20% variant allele frequency (VAF), also demonstrated reduced overall survival (12.1 months versus 42.9 months, p = 0.04).ConclusionsIn addition to identifying patients with genomic alterations suitable for clinically proven standard of care therapeutic options, the 50 gene NGS panel has significant potential in identifying potentially actionable non-tier 1 mutations and therefore may become future standard clinical practice.</div

ROC-AUC analysis of ATM, MRE11, and combined protein panel expressions with tumour regression grade (TRG).

<p>(A−C) Box plots show levels of ATM, MRE11, and their combined expression in the TC categorized by TRG as 0–2 (good response) or 3 (poor response). The association between protein expression with TRG was examined by Mann−Whitney U test (ATM, <i>P</i> = 0.27; MRE11, <i>P</i> = 0.015; and combined proteins, <i>P</i> = 0.011). (D) Receiver operating characteristic (ROC) curve analysis comparing the performance of ATM and MRE11 alone with the combined 2-protein panel.</p

Cox regression analyses of combined TC expression level with clinicopathologic variables and DFS.

<p>Cox regression analyses of combined TC expression level with clinicopathologic variables and DFS.</p