TRF2 as novel marker of tumor response to taxane-based therapy: from mechanistic insight to clinical implication

BACKGROUND

Breast Cancer (BC) can be classified, due to its heterogeneity, into multiple subtypes that differ for prognosis and clinical management. Notably, triple negative breast cancer (TNBC) - the most aggressive BC form - is refractory to endocrine and most of the target therapies. In this view, taxane-based therapy still represents the elective strategy for the treatment of this tumor. However, due variability in patients' response, management of TNBC still represents an unmet medical need. Telomeric Binding Factor 2 (TRF2), a key regulator of telomere integrity that is over-expressed in several tumors, including TNBC, has been recently found to plays a role in regulating autophagy, a degradative process that is involved in drug detoxification. Based on these considerations, we pointed, here, at investigating if TRF2, regulating autophagy, can affect tumor sensitivity to therapy.

METHODS

Human TNBC cell lines, over-expressing or not TRF2, were subjected to treatment with different taxanes and drug efficacy was tested in terms of autophagic response and cell proliferation. Autophagy was evaluated first biochemically, by measuring the levels of LC3, and then by immunofluorescence analysis of LC3-puncta positive cells. Concerning the proliferation, cells were subjected to colony formation assays associated with western blot and FACS analyses. The obtained results were then confirmed also in mouse models. Finally, the clinical relevance of our findings was established by retrospective analysis on a cohort of TNBC patients subjected to taxane-based neoadjuvant chemotherapy.

RESULTS

This study demonstrated that TRF2, inhibiting autophagy, is able to increase the sensitivity of TNBC cells to taxanes. The data, first obtained in in vitro models, were then recapitulated in preclinical mouse models and in a cohort of TNBC patients, definitively demonstrating that TRF2 over-expression enhances the efficacy of taxane-based neoadjuvant therapy in reducing tumor growth and its recurrence upon surgical intervention.

CONCLUSIONS

Based on our finding it is possible to conclude that TRF2, already known for its role in promoting tumor formation and progression, might represents an Achilles' heel for cancer. In this view, TRF2 might be exploited as a putative biomarker to predict the response of TNBC patients to taxane-based neoadjuvant chemotherapy.

A Real-World Systematic Analysis of Driver Mutations' Prevalence in Early- and Advanced-Stage NSCLC: Implications for Targeted Therapies in the Adjuvant Setting

Simple Summary

The development of oncogene-targeted drugs has radically changed the course of non small cell lung carcinoma (NSCLC) in the advanced stage. Recently, the ADAURA trial demonstrated the efficacy of Osimertinib also in the adjuvant setting of EGFR-mutated NSCLC. This raises the question regarding whether the same paradigm applies also to currently approved drugs directed against non-EGFR NSCLC drivers. Herein we compared actionable genomic alterations in early- and advanced-stage NSCLC in 1961 unselected single-institution cases analyzed by routine molecular diagnostics procedures. Our data add significantly to the currently limited real-world data on actionable mutations in surgically resectable NSCLC. Our finding that distinct NSCLC genomic drivers are mutated at similar frequencies in early- and advanced-stage tumors implies that the relative biological potency of currently actionable NSCLC genomic drivers is conserved throughout clinical evolution and supports the hypothesis that genotype-matched therapies are likely to provide significant benefit in an adjuvant setting

Abstract

The approval of osimertinib for adjuvant treatment of stage I–II–III EGFR-mutated NSCLC (early stage) represents a paradigm shift, raising the question of whether other genotype-matched therapeutics approved for advanced-stage NSCLC can also provide clinical benefit in the adjuvant setting. However, there is a paucity of real-world data on the prevalence of actionable genomic alterations (GAs) in early-stage NSCLC. We used next-generation sequencing, complemented by immunohistochemistry and fluorescence in situ hybridization, to screen our single-institution cohort of 1961 NSCLC consecutive cases for actionable molecular targets. The prevalence of actionable GAs was comparable in early versus advanced-stage NSCLC, the only exception being KRAS mutations (more frequent in early-stage cases). Consistent with advanced-stage tumors being more aggressive, co-occurrence of TP53 and EGFR GAs as well as copy number gains were less frequent in early-stage tumors. EGFR mutations and high expression of PD-L1 were inversely associated, whereas KRAS mutations and high PD-L1 reactivity showed positive association. Recapitulating advanced-stage tumors, early-stage NSCLC had the highest share of EGFR mutations in lepidic and acinar subtypes. Resected lepidic tumors contained the highest proportion of the KRAS G12C actionable variant. These results, obtained with routine diagnostic technologies in an unselected clinical setting, provide a significant addition of real-world data in early-stage NSCLC.

Not enough can be enough: feasibility of the Idylla EGFR mutation test when reuse of stained tissue slides is the only option available

AIMS

The minimally invasive procedures used in the diagnostic workup of patients with advanced non-small cell lung cancer (NSCLC) often provide poor yields of pathological material suitable for molecular analyses. Not infrequently, the DNA yield from small biopsies/cytological samples is insufficient for the assessment of genomic biomarkers that inform personalised therapies. The Idylla EGFR mutation test (IEMT) has been specifically designed to process formalin-fixed paraffin-embedded sections without requiring preliminary DNA extraction.This study aims to evaluate the diagnostic accuracy of IEMT when used to analyse archival histopathology material. More specifically, our objective was to establish whether or not different staining procedures could affect assay performance.

METHODS

Twenty NSCLC samples were selected accordingly to EGFR mutational status. To mimic archived stained material, sections were subjected to H&E staining, fluorescent in situ hybridisation analyses or immunodetection by immunohistochemistry before being processed for IEMT.

RESULTS

Parallel assessment of EGFR mutational status by IEMT on stained sections and next-generation sequencing on DNA yielded a concordant result in 50 out of 60 tests (83.3%). The discoloration of H&E of the archived sample was found to be the optimal procedure to highlight all the actionable alterations of EGFR.

CONCLUSIONS

IEMT can provide remarkable diagnostic accuracy for the assessment of EGFR mutational status also when the only source of pathological material available for molecular analyses is represented by H&E stained sections. Ad hoc supervision by a qualified molecular biologist is in any case recommended.