Cross-sectional analysis of circulating tumor DNA in primary colorectal cancer at surgery and during post-surgery follow-up by liquid biopsy

Colorectal Cancer Diagnosis through Breath Test Using a Portable Breath Analyzer-Preliminary Data

Screening methods available for colorectal cancer (CRC) to date are burdened by poor reliability and low patient adherence and compliance. An altered pattern of volatile organic compounds (VOCs) in exhaled breath has been proposed as a non-invasive potential diagnostic tool for distinguishing CRC patients from healthy controls (HC). The aim of this study was to evaluate the reliability of an innovative portable device containing a micro-gas chromatograph in enabling rapid, on-site CRC diagnosis through analysis of patients' exhaled breath. In this prospective trial, breath samples were collected in a tertiary referral center of colorectal surgery, and analysis of the chromatograms was performed by the Biomedical Engineering Department. The breath of patients with CRC and HC was collected into Tedlar bags through a Nafion filter and mouthpiece with a one-way valve. The breath samples were analyzed by an automated portable gas chromatography device. Relevant volatile biomarkers and discriminant chromatographic peaks were identified through machine learning, linear discriminant analysis and principal component analysis. A total of 68 subjects, 36 patients affected by histologically proven CRC with no evidence of metastases and 32 HC with negative colonoscopies, were enrolled. After testing a training set (18 CRC and 18 HC) and a testing set (18 CRC and 14 HC), an overall specificity of 87.5%, sensitivity of 94.4% and accuracy of 91.2% in identifying CRC patients was found based on three VOCs. Breath biopsy may represent a promising non-invasive method of discriminating CRC patients from HC.

Calibration of cell-free DNA measurements by next-generation sequencing

OBJECTIVES

Accurate monitoring of disease burden depends on accurate disease marker quantification. Although next-generation sequencing (NGS) is a promising technology for noninvasive monitoring, plasma cell-free DNA levels are often reported in misleading units that are confounded by non-disease-related factors. We proposed a novel strategy for calibrating NGS assays using spiked normalizers to improve precision and to promote standardization and harmonization of analyte concentrations.

METHODS

In this study, we refined our NGS protocol to calculate absolute analyte concentrations to (1) adjust for assay efficiency, as judged by recovery of spiked synthetic normalizer DNAs, and (2) calibrate NGS values against droplet digital polymerase chain reaction (ddPCR). As a model target, we chose the Epstein-Barr virus (EBV) genome. In patient (n = 12) and mock (n = 12) plasmas, NGS and 2 EBV ddPCR assays were used to report EBV load in copies per mL of plasma.

RESULTS

Next-generation sequencing was equally sensitive to ddPCR, with improved linearity when NGS values were normalized for spiked DNA read counts (R2 = 0.95 for normalized vs 0.91 for raw read concentrations). Linearity permitted NGS calibration to each ddPCR assay, achieving equivalent concentrations (copies/mL).

CONCLUSIONS

Our novel strategy for calibrating NGS assays suggests potential for a universal reference material to overcome biological and preanalytical variables hindering traditional NGS strategies for quantifying disease burden.

Analysis of Circulating Tumor DNA in Synchronous Metastatic Colorectal Cancer at Diagnosis Predicts Overall Patient Survival

Sporadic colorectal cancer (sCRC) initially presents as metastatic tumors in 25-30% of patients. The 5-year overall survival (OS) in patients with metastatic sCRC is 50%, falling to 10% in patients presenting with synchronous metastatic disease (stage IV). In this study, we systematically analyzed the mutations of RAS, PIK3CA and BRAF genes in circulating tumor DNA (ctDNA) and tumoral tissue DNA (ttDNA) from 51 synchronous metastatic colorectal carcinoma (SMCC) patients by real-time PCR, and their relationship with the clinical, biological and histological features of disease at diagnosis. The highest frequency of mutations detected was in the KRAS gene, in tumor biopsies and plasma samples, followed by mutations of the PIK3CA, NRAS and BRAF genes. Overall, plasma systematically contained those genetic abnormalities observed in the tumor biopsy sample from the same subject, the largest discrepancies detected between the tumor biopsy and plasma from the same patient being for mutations in the KRAS and PIK3CA genes, with concordances of genotyping results between ttDNA and ctDNA at diagnosis of 75% and 84%, respectively. Of the 51 SMCC patients in the study, 25 (49%) showed mutations in at least 1 of the 4 genes analyzed in patient plasma. From the prognostic point of view, the presence and number of the most common mutations in the RAS, PIK3CA and BRAF genes in plasma from SMCC patients are independent prognostic factors for OS. Determination of the mutational status of ctDNA in SMCC could be a key tool for the clinical management of patients.

Using Circulating Tumor DNA as a Novel Biomarker to Screen and Diagnose Colorectal Cancer: A Meta-Analysis

(1) Background: Circulating tumor DNA (ctDNA) has emerged as a promising biomarker for many kinds of tumors. However, whether ctDNA could be an accurate diagnostic biomarker in colorectal cancer (CRC) remains to be clarified. The aim of this study was to evaluate the diagnostic accuracy of ctDNA in CRC. (2) Methods: PubMed, Web of Science, and Cochrane databases were searched to identify studies reporting the use of ctDNA to screen and diagnose CRC, and all relevant studies published until October 2022 were enrolled for our analysis. These studies were divided into three primer subgroups: the subgroup of quantitative or qualitative analysis of ctDNA and the subgroup of septin9 (SEPT9) methylation assay. (3) Results: A total of 79 qualified articles with 25,240 subjects were incorporated into our meta-analysis. For quantitative studies, the combined sensitivity (SEN), specificity (SPE), and diagnostic odds ratio (DOR) were 0.723 (95% CI: 0.623-0.803), 0.920 (95% CI: 0.827-0.966), and 23.305 (95% CI: 9.378-57.906), respectively, yielding an AUC of 0.860. The corresponding values for qualitative studies were 0.610 (95% CI: 0.566-0.651), 0.891 (95% CI: 0.878-0.909), 12.569 (95% CI: 9.969-15.848), and 0.823, respectively. Detection of SEPT9 methylation depicted an AUC of 0.879, with an SEN of 0.679 (95% CI: 0.622-0.732), an SPE of 0.903 (95% CI: 0.878-0.923), and a DOR of 20.121 (95% CI:14.404-28.106), respectively. (4) Conclusion: Blood-based ctDNA assay would be a potential novel biomarker for CRC screening and diagnosis. Specifically, quantitative analysis of ctDNA or qualitative analysis of SEPT9 methylation exhibited satisfying diagnostic efficiency. Larger sample studies are needed to further confirm our conclusions and to make the ctDNA approach more sensitive and specific.

Post-operative ctDNA monitoring in stage I colon cancer: A case report

Circulating tumor DNA (ctDNA) level monitoring after surgery for colon cancer has been studied in stage II and III colon cancer to risk-stratify patients for adjuvant therapy. However, there is less data regarding the role of this diagnostic tool in the management of stage I disease, where current recommended surveillance is limited to screening colonoscopy at one year. In this report, we describe the case of a 57-year-old man with stage I colon cancer who underwent complete resection with adequate lymph node surgical sampling, normal preoperative CEA and no evidence of metastatic disease on initial imaging. The patient elected to undergo serial ctDNA monitoring after surgery. Rising ctDNA levels, five months after resection, prompted cross-sectional imaging which demonstrated metastatic disease to the liver. The patient subsequently received five cycles of leucovorin, 5-fluorouracil, oxaliplatin, and irinotecan with bevacizumab (FOLFOXIRI-Bev) and definitive microwave ablation to the liver metastases, with resulting undetectable ctDNA levels. The patient's imaging and colonoscopy one-year post-operatively showed no evidence of disease, with ctDNA levels remaining undetectable. This report highlights the value of ctDNA monitoring in patients with early-stage colon cancer and suggests that further, large-scale studies may be warranted to determine its appropriate clinical use.

Cell-Free Circulating (Tumor) DNA before Surgery as a Prognostic Factor in Non-Metastatic Colorectal Cancer: A Systematic Review

Identification of non-metastatic colorectal cancer (CRC) patients with a high risk of recurrence after tumor resection is important to select patients who might benefit from adjuvant treatment. Cell-free DNA (cfDNA) and circulating tumor DNA (ctDNA) analyses after surgery are promising biomarkers to predict recurrence in these patients. However, these analyses face several challenges and do not allow guidance of neoadjuvant treatment, which might become a novel standard option in colon cancer treatment. The prognostic value of cfDNA/ctDNA before surgery is unclear. This systematic review aims to provide an overview of publications in which the prognostic value of presurgery cfDNA/ctDNA in non-metastatic CRC patients was studied and is performed according to PRISMA guidelines. A total of 29 out of 1233 articles were included and categorized into three groups that reflect the type of approach: measurement of cfDNA, ctDNA somatic alterations, and ctDNA methylation. Overall, a clear association between presurgery cfDNA/ctDNA and the outcome was not observed, but large studies that primarily focus on the prognostic value of presurgery cfDNA/ctDNA are lacking. Designing and performing studies that focus on the value of presurgery cfDNA/ctDNA is needed, in addition to standardization in the reporting of cfDNA/ctDNA results according to existing guidelines to improve comparability and interpretation among studies.

Error Characterization and Statistical Modeling Improves Circulating Tumor DNA Detection by Droplet Digital PCR

BACKGROUND

Droplet digital PCR (ddPCR) is a widely used and sensitive application for circulating tumor DNA (ctDNA) detection. As ctDNA is often found in low abundance, methods to separate low-signal readouts from noise are necessary. We aimed to characterize the ddPCR-generated noise and, informed by this, create a sensitive and specific ctDNA caller.

METHODS

We built 2 novel complimentary ctDNA calling methods: dynamic limit of blank and concentration and assay-specific tumor load estimator (CASTLE). Both methods are informed by empirically established assay-specific noise profiles. Here, we characterized noise for 70 mutation-detecting ddPCR assays by applying each assay to 95 nonmutated samples. Using these profiles, the performance of the 2 new methods was assessed in a total of 9447 negative/positive reference samples and in 1311 real-life plasma samples from colorectal cancer patients. Lastly, performances were compared to 7 literature-established calling methods.

RESULTS

For many assays, noise increased proportionally with the DNA input amount. Assays targeting transition base changes were more error-prone than transversion-targeting assays. Both our calling methods successfully accounted for the additional noise in transition assays and showed consistently high performance regardless of DNA input amount. Calling methods that were not noise-informed performed less well than noise-informed methods. CASTLE was the only calling method providing a statistical estimate of the noise-corrected mutation level and call certainty.

CONCLUSIONS

Accurate error modeling is necessary for sensitive and specific ctDNA detection by ddPCR. Accounting for DNA input amounts ensures specific detection regardless of the sample-specific DNA concentration. Our results demonstrate CASTLE as a powerful tool for ctDNA calling using ddPCR.

Liquid biopsy with droplet digital PCR targeted to specific mutations in plasma cell-free tumor DNA can detect ovarian cancer recurrence earlier than CA125

OBJECTIVE

Ovarian cancer (OC) is an intractable gynecological tumor, and frequent recurrence is experienced within a few years even after the complete eradication of tumor tissues by radical resection and neo-adjuvant chemotherapies. The conventional recurrence marker, CA125, is widely used for follow-up after resection of OC, but CA125 has a long half-life in blood and lacks dynamic responses to tumor recurrence. Recent developments in liquid biopsy procedures are expected to overcome the difficulties in early diagnosis of OC recurrence after surgery.

METHODS

We applied droplet digital PCR (ddPCR) technology to detect circulating tumor-derived DNA in OC patients' plasma during follow-up. Exome sequencing of 11 tumor-normal pairs of genomic DNA from consecutive OC patients identified tumor-specific mutations, and ddPCR probes were selected for each sample.

RESULTS

Six of 11 cases showed apparent recurrence during follow-up (mean progression-free survival was 348.3 days) and all six cases were positive in ddPCR analyses. In addition, ddPCR became positive before increased plasma CA125 in five out of six cases. Increased allele frequency of circulating tumor DNA (ctDNA) is associated with increased tumor volume after recurrence. ddPCR detected ctDNA signals significantly earlier than increased CA125 in the detection of OC recurrence by imaging (49 days and 7 days before, respectively: p < 0.05). No ctDNA was detected in the plasma of recurrence-free cases.

CONCLUSIONS

Our results demonstrate the potential of identifying ctDNA by ddPCR as an early detection tool for OC recurrence.

Clinical Applications of Minimal Residual Disease Assessments by Tumor-Informed and Tumor-Uninformed Circulating Tumor DNA in Colorectal Cancer

Simple Summary

Circulating tumor DNA, or ctDNA, are fragments of tumor DNA that can be detected in the blood of patients with colorectal cancer. Measuring ctDNA levels in the blood has shown the potential to provide important information that can be helpful in the clinical care of patients with colorectal cancer. For example, in patients with colon cancer that has been removed by surgery, measuring ctDNA in the blood can predict the likelihood of cancer recurrence, while in those with metastatic colorectal cancer, measuring ctDNA can inform the clinician whether chemotherapy is effective at earlier timepoints than currently available tests. In this review, we discuss the results from ongoing studies describing the utility of ctDNA measurements across all stages of colorectal cancer. We also discuss the various clinical scenarios that ctDNA may have the most immediate impact in colorectal cancer management.

Abstract

Emerging data suggest that circulating tumor DNA (ctDNA) can detect colorectal cancer (CRC)-specific signals across both non-metastatic and metastatic settings. With the development of multiple platforms, including tumor-informed and tumor-agnostic ctDNA assays and demonstration of their provocative analytic performance to detect minimal residual disease, there are now ongoing, phase III randomized clinical trials to evaluate their role in the management paradigm of CRC. In this review, we highlight landmark studies that have formed the basis for ongoing studies on the clinically applicability of plasma ctDNA assays in resected, stage I–III CRC and metastatic CRC. We discuss clinical settings by which ctDNA may have the most immediate impact in routine clinical practice. These include the potential for ctDNA to (1) guide surveillance and intensification or de-intensification strategies of adjuvant therapy in resected, stage I–III CRC, (2) predict treatment response to neoadjuvant therapy in locally advanced rectal cancer inclusive of total neoadjuvant therapy (TNT), and (3) predict response to systemic and surgical therapies in metastatic disease. We end by considering clinical variables that can influence our ability to reliably interpret ctDNA dynamics in the clinic.

Clinical Applications of Circulating Tumor Cells and Circulating Tumor DNA as a Liquid Biopsy Marker in Colorectal Cancer

Simple Summary

Colorectal cancer is one of the most frequent malignant tumors worldwide and the spread of tumor cells through the blood circulation followed by the colonization of distant organs (“metastases”) is the main cause of cancer-related death. The blood is, therefore, an important fluid that can be explored for diagnostic purposes. Liquid biopsy is a new diagnostic concept defined as the analysis of circulating tumor cells or cellular products such as cell-free DNA in the blood or other body fluids of cancer patients. In this review, we summarize and discuss the latest findings using circulating tumor cells and cell-free DNA derived from tumor lesions in the blood of patients with colorectal cancer. Clinical applications include early detection of cancer, identification of patients with a high risk for disease progression after curative surgery, monitoring for disease progression in the context of cancer therapies, and discovery of mechanisms of resistance to therapy.

Abstract

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. It is a heterogeneous tumor with a wide genomic instability, leading to tumor recurrence, distant metastasis, and therapy resistance. Therefore, adjunct non-invasive tools are urgently needed to help the current classical staging systems for more accurate prognostication and guiding personalized therapy. In recent decades, there has been an increasing interest in the diagnostic, prognostic, and predictive value of circulating cancer-derived material in CRC. Liquid biopsies provide direct non-invasive access to tumor material, which is shed into the circulation; this enables the analysis of circulating tumor cells (CTC) and genomic components such as circulating free DNA (cfDNA), which could provide the key for personalized therapy. Liquid biopsy (LB) allows for the identification of patients with a high risk for disease progression after curative surgery, as well as longitudinal monitoring for disease progression and therapy response. Here, we will review the most recent studies on CRC, demonstrating the clinical potential and utility of CTCs and ctDNA. We will discuss some of the advantages and limitations of LBs and the future perspectives in the field of CRC management.

Detection of Tumor DNA in Human Plasma with a Functional PLL-Based Surface Layer and Plasmonic Biosensing

Standard protocols for the analysis of circulating tumor DNA (ctDNA) include the isolation of DNA from the patient's plasma and its amplification and analysis in buffered solutions. The application of such protocols is hampered by several factors, including the complexity and time-constrained preanalytical procedures, risks for sample contamination, extended analysis time, and assay costs. A recently introduced nanoparticle-enhanced surface plasmon resonance imaging-based assay has been shown to simplify procedures for the direct detection of tumor DNA in the patient's plasma, greatly simplifying the cumbersome preanalytical phase. To further simplify the protocol, a new dual-functional low-fouling poly-l-lysine (PLL)-based surface layer has been introduced that is described herein. The new PLL-based layer includes a densely immobilized CEEEEE oligopeptide to create a charge-balanced system preventing the nonspecific adsorption of plasma components on the sensor surface. The layer also comprises sparsely attached peptide nucleic acid probes complementary to the sequence of circulating DNA, e.g., the analyte that has to be captured in the plasma from cancer patients. We thoroughly investigated the contribution of each component of the dual-functional polymer to the antifouling properties of the surface layer. The low-fouling property of the new surface layer allowed us to detect wild-type and KRAS p.G12D-mutated DNA in human plasma at the attomolar level (∼2.5 aM) and KRAS p.G13D-mutated tumor DNA in liquid biopsy from a cancer patient with almost no preanalytical treatment of the patient's plasma, no need to isolate DNA from plasma, and without PCR amplification of the target sequence.

Content of circulating tumor DNA depends on the tumor type and the dynamics of tumor size, but is not influenced significantly by physical exercise, time of the day or recent meal

PURPOSE

This study aimed to investigate factors, which influence the content of circulating tumor DNA (ctDNA).

METHODS

398 serial plasma samples were collected within 1-7 consecutive days from patients with EGFR-mutated lung cancer (n = 13), RAS/RAF-mutated colorectal cancer (n = 54) and BRAF-mutated melanoma (n = 17), who presented with measurable tumor disease. The amount of ctDNA was determined by ddPCR.

RESULTS

Among 82 patients, who donated 2-6 serial plasma samples, 42 subjects were classified as ctDNA-positive; only 22% cases were mutation-positive across all consecutive tests, while 24/82 (29%) patients showed presence of mutated ctDNA in some but not all blood draws. Subjects with progressing tumors had higher probability of being detected ctDNA-positive as compared to patients, who responded to therapy or had stable disease (39/55 (71%) vs. 4/24 (17%); p = 0.0001). Our study failed to reveal the impact of the time of the day, recent meal or prior physical exercise on the results of ctDNA testing.

CONCLUSIONS

Presence of ctDNA in plasma is particularly characteristic for patients, who experience clinical progression of tumor disease. Consecutive plasma tests may occasionally provide discordant data; thus, the repetition of analysis may be advised in certain cases in order to ensure the validity of negative ctDNA result.

Precision Medicine and Melanoma: Multi-Omics Approaches to Monitoring the Immunotherapy Response

The treatment and management of patients with metastatic melanoma have evolved considerably in the "era" of personalized medicine. Melanoma was one of the first solid tumors to benefit from immunotherapy; life expectancy for patients in advanced stage of disease has improved. However, many progresses have yet to be made considering the (still) high number of patients who do not respond to therapies or who suffer adverse events. In this scenario, precision medicine appears fundamental to direct the most appropriate treatment to the single patient and to guide towards treatment decisions. The recent multi-omics analyses (genomics, transcriptomics, proteomics, metabolomics, radiomics, etc.) and the technological evolution of data interpretation have allowed to identify and understand several processes underlying the biology of cancer; therefore, improving the tumor clinical management. Specifically, these approaches have identified new pharmacological targets and potential biomarkers used to predict the response or adverse events to treatments. In this review, we will analyze and describe the most important omics approaches, by evaluating the methodological aspects and progress in melanoma precision medicine.

The Promise of Circulating Tumor DNA (ctDNA) in the Management of Early-Stage Colon Cancer: A Critical Review

Simple Summary

Currently, the treatment for localized colon cancer consists of surgery and, if the presence of residual cancer cells is suspected, chemotherapy following the surgery. However, the current standard tools to determine the presence of residual cancer after the surgery are imprecise, which results in under- or overtreatment in a significant number of patients. Emerging research indicates that circulating tumor DNA (ctDNA) can reveal the presence of residual cancer after surgery with much higher precision than the presently available tools, and can help with the treatment decision regarding a need for chemotherapy after the surgery. Furthermore, ctDNA can potentially help determine the effectiveness of chemotherapy and detect cancer recurrence much earlier than the current standard tools. In this review, we have critically evaluated available data to provide the readers with an overview of how ctDNA can potentially transform the treatment of localized colon cancer in the near future.

Abstract

The current standard treatment for patients with early-stage colon cancer consists of surgical resection, followed by adjuvant therapy in a select group of patients deemed at risk of cancer recurrence. The decision to administer adjuvant therapy, intended to eradicate the clinically inapparent minimal residual disease (MRD) to achieve a cure, is guided by clinicopathologic characteristics of the tumor. However, the risk stratification based on clinicopathologic characteristics is imprecise and results in under or overtreatment in a substantial number of patients. Emerging research indicates that the circulating tumor DNA (ctDNA), a fraction of cell-free DNA (cfDNA) in the bloodstream that originates from the neoplastic cells and carry tumor-specific genomic alterations, is a promising surrogate marker of MRD. Several recent studies suggest that ctDNA-guided risk stratification for adjuvant therapy outperforms existing clinicopathologic prognostic indicators. Preliminary data also indicate that, aside from being a prognostic indicator, ctDNA can inform on the efficacy of adjuvant therapy, which is the underlying scientific rationale for several ongoing clinical trials evaluating ctDNA-guided therapy escalation or de-escalation. Furthermore, serial monitoring of ctDNA after completion of definitive therapy can potentially detect cancer recurrence much earlier than conventional surveillance methods that may provide a critical window of opportunity for additional curative-intent therapeutic interventions. This article presents a critical overview of published studies that evaluated the clinical utility of ctDNA in the management of patients with early-stage colon cancer, and the potential of ctDNA to transform the adjuvant therapy strategies.

Direct plasmonic detection of circulating RAS mutated DNA in colorectal cancer patients

RAS mutations in the blood of colorectal cancer (CRC) patients are emerging as biomarkers of acquired resistance to Epidermal Growth Factor Receptor therapy. Unfortunately, reliable assays granting fast, real-time monitoring of treatment response, capable of refining retrospective, tissue-based analysis, are still needed. Recently, several methods for detecting blood RAS mutations have been proposed, generally relying on multi-step and PCR-based, time-consuming and cost-ineffective procedures. By exploiting a liquid biopsy approach, we developed an ultrasensitive nanoparticle-enhanced plasmonic method for detecting ~1 aM RAS single nucleotide variants (SNVs) in the plasma of CRC patients. The assay does not require the extraction of tumor DNA from plasma and detects it in volumes as low as 40 μL of plasma, which is at least an order of magnitude smaller than that required by state of the art liquid biopsy technologies. The most prevalent RAS mutations are detected in DNA from tumor tissue with 100% sensitivity and 83.33% specificity. Spike-in experiments in human plasma further encouraged assay application on clinical specimens. The assay was proven in plasma from CRC patients and healthy donors, and full discrimination between mutated DNA from patients over wild-type DNA from healthy volunteers was obtained thus demonstrating its promising avenue for cancer monitoring based on liquid biopsy.

TMPRSS2, a SARS-CoV-2 internalization protease is downregulated in head and neck cancer patients

Background

SARS-coronavirus-2 enters host cells through binding of the Spike protein to ACE2 receptor and subsequent S priming by the TMPRSS2 protease. We aim to assess differences in both ACE2 and TMPRSS2 expression in normal tissues from oral cavity, pharynx, larynx and lung tissues as well as neoplastic tissues from the same areas.

Methods

The study has been conducted using the TCGA and the Regina Elena Institute databases and validated by experimental model in HNSCC cells. We also included data from one COVID19 patient who went under surgery for HNSCC.

Results

TMPRSS2 expression in HNSCC was significantly reduced compared to the normal tissues. It was more evident in women than in men, in TP53 mutated versus wild TP53 tumors, in HPV negative patients compared to HPV positive counterparts. Functionally, we modeled the multivariate effect of TP53, HPV, and other inherent variables on TMPRSS2. All variables had a statistically significant independent effect on TMPRSS2. In particular, in tumor tissues, HPV negative, TP53 mutated status and elevated TP53-dependent Myc-target genes were associated with low TMPRSS2 expression. The further analysis of both TCGA and our institutional HNSCC datasets identified a signature anti-correlated to TMPRSS2. As proof-of-principle we also validated the anti-correlation between microRNAs and TMPRSS2 expression in a SARS-CoV-2 positive HNSCC patient tissues Finally, we did not find TMPRSS2 promoter methylation.

Conclusions

Collectively, these findings suggest that tumoral tissues, herein exemplified by HNSCC and lung cancers might be more resistant to SARS-CoV-2 infection due to reduced expression of TMPRSS2. These observations may help to better assess the frailty of SARS-CoV-2 positive cancer patients.