Mutant allele tumor heterogeneity (MATH) and head and neck squamous cell carcinoma

The American Joint Committee on Cancer (AJCC) Breast Cancer Staging, Eighth Edition, is more Reflective of Cancer Biology than the Seventh Edition

BACKGROUND

The American Joint Committee on Cancer (AJCC) eighth-edition breast cancer staging system incorporating tumor grade, hormone/human epidermal growth factor receptor 2 (HER2) receptor status, and genomic assays has demonstrated better prognostic value than the seventh edition. Given the crucial role of cancer biology in prognosis, the authors hypothesized that the AJCC eighth-edition criteria offer better biologic differentiation between stages than the seventh edition.

METHODS

This study analyzed 696 breast cancer patients from The Cancer Genome Atlas (TCGA) and Text Information Extraction System (TIES) database, with complete information available for staging according to both the AJCC seventh- and eighth-edition criteria.

RESULTS

The study indicated an increase in the number of patients classified as stage I in the eighth edition compared with the seventh edition, particularly in hormone-positive breast cancers. Furthermore, the eighth edition demonstrated improved discrimination in overall survival between stages I and II cancers. The eighth edition was able to distinguish significant differences in cell proliferation, intratumor heterogeneity, homologous recombination deficiency, and neoantigen load between stages I and II cancers. Moreover, the eighth edition more clearly differentiated immune cell infiltration between stages II and I cancer than the seventh edition. Finally, immune activity and gene expression of immune checkpoints such as PDCD1, PDL1, CTLA4, LAG3, TIGIT, and IDO1 and 2 showed a more pronounced difference between stages I and II cancers in the eighth edition than in the seventh edition.

CONCLUSION

The AJCC eighth edition breast cancer staging system better distinguishes cancers with more aggressive biology than the seventh edition.

Exploring the role of ADAMTSL2 across multiple cancer types: A pan-cancer analysis and validated in colorectal cancer

BACKGROUND

Recent studies have established a correlation between ADAMTSL2 (ADAMTS-like 2) and the development of various cancers. This study aims to conduct a comprehensive pan-cancer analysis in 37 cancer types and investigate its potential role in colon and rectal adenocarcinoma (COADREAD).

METHOD

Pan-cancer and mutation data were sourced from The Cancer Genome Atlas (TCGA) database and analyzed using Sangerbox analysis platform. We explored the expression patterns and prognostic implications of ADAMTSL2, and investigated its relationships with tumor heterogeneity, stemness, immune checkpoint genes, immune cell infiltration, RNA modifications, and mutational profiles across different cancers. Additionally, with Ethics Committee approval, we conducted immunohistochemical (IHC) analysis on 120 COADEAD samples to evaluate ADAMTSL2 expression and its association with clinicopathological parameters.

RESULTS

ADAMTSL2 expression was positively correlated with the hazard ratio of OS, DSS, DFI and PFI for ESCA and COADREAD. A negative correlation was observed between ADAMTSL2 expression and NEO levels in COAD. Gene alterations in ADAMTSL2 were observed, with a mutation frequency of 5.0% in COAD. There is a significant correlation between ADAMTSL2 expression and immune cell infiltration in a variety of cancers. The expression level of ADAMTSL2 protein was associated with T stage, N stage, M stage (p < 0.05). Kaplan‒Meier survival curves demonstrated that the high ADAMTSL2 group had a shorter OS time (p = 0.047) and progression free survival time (p = 0.026) than the low ADAMTSL2 group.

CONCLUSION

In summary, we conducted a comprehensive pan-cancer analysis of ADAMTSL2 and we demonstrated that ADAMTSL2 may serve as a novel prognostic biomarker and immunotherapy target in COADREAD.

On the Boundary of Exploratory Genomics and Translation in Sequential Glioblastoma

OMICS methods brought significant advancements to the understanding of tumor cell biology, which transformed the treatment and prognosis of several cancers. Clinical practice and outcomes, however, changed significantly less in the case of glioblastoma (GBM). In this study, we aimed to assess the utility of whole exome (WES) sequencing in the clinical setting. Ten pairs of formalin-fixed, paraffin-embedded (FFPE) GBM specimens were obtained at onset (GBM-P) and at recurrence (GBM-R). Histopathological and molecular features of all samples supported the diagnosis of GBM based on WHO CNS5. WES data were filtered, applying a strict and custom-made pipeline, and occurrence of oncogenic and likely oncogenic variants in GBM-P, GBM-R or both were identified by using the VarSeq program version 2.5.0 (Golden Helix, Inc.). Characteristics and recurrence of the variants were analyzed in our own cohort and were also compared to those available in the COSMIC database. The lists of oncogenic and likely oncogenic variants corresponded to those identified in other studies. The average number of these variants were 4 and 5 out of all detected 24 and 34 variants in GBM-P and GBM-R samples, respectively. On average, one shared oncogenic/likely oncogenic variant was found in the pairs. We assessed the identified variants' therapeutic significance, also taking into consideration the guidelines by the Association for Molecular Pathology (AMP). Our data support that a thorough WES analysis is suitable for identifying oncogenic and likely oncogenic variants in an individual clinical sample or a small cohort of FFPE glioma specimens, which concur with those of comprehensive research studies. Such analyses also allow us to monitor molecular dynamics of sequential GBM. In addition, careful evaluation of data according to the AMP guideline reveal that though therapeutic applicability of the variants is generally limited in the clinic, such information may be valuable in selected cases, and can support innovative preclinical and clinical trials.

Genomic heterogeneity at baseline is associated with T790M resistance mutations in EGFR-mutated lung cancer treated with the first-/second-generation tyrosine kinase inhibitors

This study analyzed whether extended molecular profiling can predict the development of epidermal growth factor receptor (EGFR) gene T790M mutation, which is the most frequent resistance alteration in non-small cell lung cancer (NSCLC) after treatment with the first-/second-generation (1G/2G) EGFR inhibitors (tyrosine kinase inhibitors [TKIs]), but only weakly associated with clinical characteristics. Whole exome sequencing (WES) was performed on pretreatment tumor tissue with matched normal samples from NSCLC patients with (n = 25, detected in tissue or blood rebiopsies) or without (n = 14, negative tissue rebiopsies only) subsequent EGFR p.T790M mutation after treatment with 1G/2G EGFR TKI. Several complex genetic biomarkers were assessed using bioinformatic methods. After treatment with first-line afatinib (44%) or erlotinib/gefitinib (56%), median progression-free survival and overall survival were 12.1 and 33.7 months, respectively. Clinical and tumor genetic characteristics, including age (median, 66 years), sex (74% female), smoking (69% never/light smokers), EGFR mutation type (72% exon 19 deletions), and TP53 mutations (41%) were not significantly associated with T790M mutation (p > 0.05). By contrast, complex biomarkers including tumor mutational burden, the clock-like mutation signature SBS1 + 5, tumor ploidy, and markers of subclonality including mutant-allele tumor heterogeneity, subclonal copy number changes, and median tumor-adjusted variant allele frequency were significantly higher at baseline in tumors with subsequent T790M mutation (all p < 0.05). Each marker alone could predict subsequent development of T790M with an area under the curve (AUC) of 0.72-0.77, but the small number of cases did not allow confirmation of better performance for biomarker combinations in leave-one-out cross-validated logistic regression (AUC 0.69, 95% confidence interval: 0.50-0.87). Extended molecular profiling with WES at initial diagnosis reveals several complex biomarkers associated with subsequent development of T790M resistance mutation in NSCLC patients receiving first-/second-generation TKIs as the first-line therapy. Larger prospective studies will be necessary to define a forecasting model.

Unrevealing the therapeutic benefits of radiotherapy and consolidation immunotherapy using ctDNA-defined tumor clonality in unresectable locally advanced non-small cell lung cancer

Progression occurs in approximately two-thirds of patients with locally advanced non-small cell lung cancer (LA-NSCLC) receiving chemoradiation and consolidation immunotherapy. Molecular indicators for outcome prediction are under development. A novel metric, the ratio of mean to max variant allele frequency (mmVAF), was derived from 431 pre-treatment tissue biopsies from The Cancer Genome Atlas and evaluated in serial circulating tumor DNA (ctDNA) from 70 LA-NSCLC patients receiving definitive radiotherapy/chemoradiotherapy (RT/CRT) with/without immunotherapy. High mmVAFs in pre-treatment tissue biopsies, indicating clonal predominant tumors (P < 0.01), were associated with inferior overall survival [OS, hazard ratio (HR): 1.48, 95 % confidence interval (CI): 1.11-1.98]. Similar associations of mmVAF with clonality (P < 0.01) and OS (HR: 2.24, 95 % CI: 0.71-7.08) were observed in pre-treatment ctDNA. At 1-month post-RT, ctDNA mmVAF-high patients receiving consolidation immunotherapy exhibited improved progression-free survival (PFS) compared to those who did not (HR: 0.14, 95 % CI: 0.03-0.67). From the baseline to week 4 of RT and/or 1-month post-RT, survival benefits from consolidation immunotherapy were exclusively observed in ctDNA mmVAF-increased patients (PFS, HR: 0.39, 95 % CI: 0.14-1.15), especially in terms of distant metastasis (HR: 0.11, 95 % CI: 0.01-0.95). In summary, our longitudinal data demonstrated the applicability of ctDNA-defined clonality for prognostic stratification and immunotherapy benefit prediction in LA-NSCLC.

Clonal architecture and evolutionary history of Waldenström's macroglobulinemia at the single-cell level

To provide insight into the subclonal architecture and co-dependency patterns of the alterations in Waldenström's macroglobulinemia (WM), we performed single-cell mutational and protein profiling of eight patients. A custom panel was designed to screen for mutations and copy number alterations at the single-cell level in samples taken from patients at diagnosis (n=5) or at disease progression (n=3). Results showed that in asymptomatic WM at diagnosis, MYD88L265P was the predominant clonal alteration; other events, if present, were secondary and subclonal to MYD88L265P. In symptomatic WM, clonal diversity was more evident, uncovering combinations of alterations that synergized to promote clonal expansion and dominance. At disease progression, a dominant clone was observed, sometimes accompanied by other less complex minor clones, which could be consistent with a clonal selection process. Clonal diversity was also reduced, probably due to the effect of treatment. Finally, we combined protein expression with mutational analysis to map somatic genotype with the immunophenotype. Our findings provide a comprehensive view of the clonality of tumor populations in WM and how clonal complexity can evolve and impact disease progression.

Comparison of next generation sequencing, droplet digital PCR, and quantitative real-time PCR for the earlier detection and quantification of HPV in HPV-positive oropharyngeal cancer

BACKGROUND

Human papillomavirus (HPV) causes nearly 80% of oropharynx cancers diagnosed in the United States, with incidence increasing each year. Analysis of cfDNA in plasma and oral rinse has the potential to detect these cases earlier than their typical presentation, but their utility and the best method to detect HPV in plasma and oral rinse samples is unknown.

MATERIALS AND METHODS

We directly compared next generation sequencing (NGS), droplet digital PCR (ddPCR), and quantitative real-time PCR (qPCR) for their ability to detect HPV16 DNA in plasma and oral rinse from 66 patients diagnosed with HPV16-positive oropharyngeal cancer (HPV16-OPC).

RESULTS

HPV DNA detection by NGS and ddPCR in plasma samples both had good sensitivity (70%) for HPV16-OPC compared to 20.6% sensitivity by qPCR (p < 0.001). In oral rinse, NGS demonstrated a superior sensitivity of 75.0% as compared to both ddPCR (8.3%, p < 0.001) and qPCR (2.1%, p < 0.001). In a limited cohort of follow up patients, HPV levels detected in plasma by NGS but not ddPCR or qPCR reflected disease remission or progression.

CONCLUSIONS

These results suggest that NGS has the best sensitivity for detecting HPV in both plasma and oral rinse and may play a role in monitoring patients for disease recurrence. Additional studies are needed to define the specificity of NGS for similar patient cohorts.

Integrated Analysis of MATH-Based Subtypes Reveals a Novel Screening Strategy for Early-Stage Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is a frequently diagnosed cancer type, and many patients have already reached an advanced stage when diagnosed. Thus, it is crucial to develop a novel and efficient approach to diagnose and classify lung adenocarcinoma at an early stage. In our study, we combined in silico analysis and machine learning to develop a new five-gene–based diagnosis strategy, which was further verified in independent cohorts and in vitro experiments. Considering the heterogeneity in cancer, we used the MATH (mutant-allele tumor heterogeneity) algorithm to divide patients with early-stage LUAD into two groups (C1 and C2). Specifically, patients in C2 had lower intratumor heterogeneity and higher abundance of immune cells (including B cell, CD4 T cell, CD8 T cell, macrophage, dendritic cell, and neutrophil). In addition, patients in C2 had a higher likelihood of immunotherapy response and overall survival advantage than patients in C1. Combined drug sensitivity analysis (CTRP/PRISM/CMap/GDSC) revealed that BI-2536 might serve as a new therapeutic compound for patients in C1. In order to realize the application value of our study, we constructed the classifier (to classify early-stage LUAD patients into C1 or C2 groups) with multiple machine learning and bioinformatic analyses. The 21-gene–based classification model showed high accuracy and strong generalization ability, and it was verified in four independent validation cohorts. In summary, our research provided a new strategy for clinicians to make a quick preliminary assisting diagnosis of early-stage LUAD and make patient classification at the intratumor heterogeneity level. All data, codes, and study processes have been deposited to Github and are available online.

Extracellular sialyltransferase st6gal1 in breast tumor cell growth and invasiveness

The sialyltransferase ST6GAL1 that adds α2-6 linked sialic acids to N-glycans of cell surface and secreted glycoproteins is prominently associated with many human cancers. Tumor-native ST6GAL1 promotes tumor cell behaviors such as invasion and resistance to cell stress and chemo- and radio-treatments. Canonically, ST6GAL1 resides in the intracellular secretory apparatus and glycosylates nascent glycoproteins in biosynthetic transit. However, ST6GAL1 is also released into the extracellular milieu and extracellularly remodels cell surface and secreted glycans. The impact of this non-canonical extrinsic mechanism of ST6GAL1 on tumor cell pathobiology is not known. We hypothesize that ST6GAL1 action is the combined effect of natively expressed sialyltransferase acting cell-autonomously within the ER-Golgi complex and sialyltransferase from extracellular origins acting extrinsically to remodel cell-surface glycans. We found that shRNA knockdown of intrinsic ST6GAL1 expression resulted in decreased ST6GAL1 cargo in the exosome-like vesicles as well as decreased breast tumor cell growth and invasive behavior in 3D in vitro cultures. Extracellular ST6GAL1, present in cancer exosomes or the freely soluble recombinant sialyltransferase, compensates for insufficient intrinsic ST6GAL1 by boosting cancer cell proliferation and increasing invasiveness. Moreover, we present evidence supporting the existence novel but yet uncharacterized cofactors in the exosome-like particles that potently amplify extrinsic ST6GAL1 action, highlighting a previously unknown mechanism linking this enzyme and cancer pathobiology. Our data indicate that extracellular ST6GAL1 from remote sources can compensate for cellular ST6GAL1-mediated aggressive tumor cell proliferation and invasive behavior and has great clinical potential for extracellular ST6GAL1 as these molecules are in the extracellular space should be easily accessible targets.

Quantifying smoking exposure, genomic correlates, and related risk of treatment failure in p16+ squamous cell carcinoma of the oropharynx

OBJECTIVES

HPV-associated (p16+) squamous cell carcinoma of the oropharynx (OPSCC) has improved survival as compared to HPV-negative, smoking-associated disease. Intermediate outcomes have been noted in patients with p16+ tumors and smoking exposure. However, the extent of smoking exposure required for outcomes to decrease has not been delineated due to low failure rates and poor availability of quantitative tobacco smoke exposure data. Our primary objective is to characterize the dose-dependent relationship between recurrence-free survival (RFS) and tobacco smoke exposure in p16+ OPSCC and secondarily correlate tobacco smoke exposure with genomic alterations.

METHODS

Single institution chart review was performed of patients diagnosed with p16+ OPSCC from 2003 to 2015. Patients were excluded if staging, treatment details, recurrence status, or smoking exposure in pack-years were not available. Two hundred and forty-four patients were included.

RESULTS

Patients with 25 pack-years or greater smoking history exhibited a dose-dependent decrease in RFS compared to never smokers. This was robust to multivariate analysis for including staging and demographic factors. Forty-three patients with available targeted tumor sequencing data were identified. A strong trend was observed for increased C to A transversion mutations above 25 pack-years, which are known to be associated with exposure to tobacco smoke. Similarly, the proportion of COSMIC Signature 4 mutations were also found to be more common in patients with more than 25 pack-years of smoking exposure.

CONCLUSION

Evidence-based smoking exposure thresholds are needed to define inclusion criteria for trials of de-escalation therapy for p16+ OPSCC. Patients with smoking exposure greater than 20 pack-years have increased risk of recurrence and a distinct pattern of genomic alterations. Further studies are needed to delineate the potential consequences of mild smoking exposure. Smoking-related mutational signatures may hold potential for biomarker development in p16+ OPSCC.

LEVEL OF EVIDENCE

2B.

Immune cytolytic activity is associated with reduced intra-tumoral genetic heterogeneity and with better clinical outcomes in triple negative breast cancer

Evaluation of the functional aspects if the tumor immune microenvironment (TIME), such as the recently introduced cytolytic activity score (CYT) index have been under the spotlight in cancer research; however, clinical relevance of immune cell killing activity in breast cancer has never been analyzed in large patient cohorts. We hypothesized that CYT reflects the immune activity of TIME and can predict patient survival. A total of 7533 breast cancer patients were analyzed as both discovery and validation cohorts. We found that high CYT was associated with advanced histological grade and triple-negative breast cancer (TNBC). High CYT in tumors was significantly associated with better survival in TNBC, but unexpectedly, not in other breast cancer subtypes. High CYT TNBC included both favorable immune-related, as well as unfavorable (suppressive) inflammation-related gene sets, and characterized by high infiltration with T cells and B cells. High CYT TNBC was associated with high homologous recombination deficiency and low somatic copy number alteration score and less mutant allele tumor heterogeneity, but not with tumor mutation burden (TMB). Although CYT was not associated with pathological complete response after neoadjuvant chemotherapy, it was significantly associated with high expression of multiple immune checkpoint molecules. In conclusion, CYT of TNBC is associated with enhanced anti-cancer immunity, less intra-tumoral heterogeneity, and with better survival.

Epithelial-Mesenchymal Transition Associated with Head and Neck Squamous Cell Carcinomas: A Review

Head and neck squamous cell carcinomas (HNSCCs) are aggressive, recurrent, and metastatic neoplasms with a high occurrence around the world and can lead to death when not treated appropriately. Several molecules and signaling pathways are involved in the malignant conversion process. Epithelial-mesenchymal transition (EMT) has been described in HNSCCs, a major type of aggressive carcinoma. EMT describes the development of epithelial cells into mesenchymal cells, which depends on several molecular interactions and signaling pathways that facilitate mesenchymal conversion. This is related to interactions with the microenvironment of the tumor, hypoxia, growth factors, matrix metalloproteinases, and the presence of viral infections. In this review, we focus on the main molecules related to EMT, their interactions with the tumor microenvironment, plasticity phenomena, epigenetic regulation, hypoxia, inflammation, their relationship with immune cells, and the inhibition of EMT in the context of HNSCCs.

Comprehensive analysis of DNA damage repair in squamous cell carcinoma subtypes

AIMS

Defective components resulting from DNA damage and repair mechanisms have been found to be underlying causes that affect the development and progression of different types of cancers, including squamous cell carcinoma (SCC). A more detailed classification of SCC is necessary for better application of DNA damage repair therapies.

MATERIALS AND METHODS

We aimed to characterize the molecular profile of SCC by developing a classification system based on DNA damage repair gene expression profiles. An integrative analysis was performed using a metadata set of 1374 SCC human samples from the UCSC Genome Browser. We then analyzed genomic alterations and mutations, and genes-TF-microRNA regulatory relationships and conducted enrichment, survival, and immune infiltration analyses.

KEY FINDINGS

This study was conducted on a total of 1374 SCC patients and 402 DNA damage repair genes. Two subtypes were established using consensus clustering, with 1143 patients being of the Non DDR subtype and 231 patients being of the DDR subtype. MATH, mutation burden, and heterogeneity were significantly higher in Non-DDR subtype than in DDR subtype. Next, a total of 1081 differentially expressed genes and 21 microRNAs were identified between the two subtypes and a genes-TF-microRNA regulatory network was constructed. In addition, stromal score, immune score and ESTIMATE score were significantly lower for the Non-DDR subtype, while tumor purity was significantly lower for the DDR subtype. In addition, five pathways associated with DNA damage repair were all enriched in the DDR subtype.

SIGNIFICANCE

Our study established two subtypes of SCC based on DNA damage repair, which may help to predict prognosis and determine the most suitable treatment for SCC patients.

Characterizing genetic intra-tumor heterogeneity across 2,658 human cancer genomes

Intra-tumor heterogeneity (ITH) is a mechanism of therapeutic resistance and therefore an important clinical challenge. However, the extent, origin, and drivers of ITH across cancer types are poorly understood. To address this, we extensively characterize ITH across whole-genome sequences of 2,658 cancer samples spanning 38 cancer types. Nearly all informative samples (95.1%) contain evidence of distinct subclonal expansions with frequent branching relationships between subclones. We observe positive selection of subclonal driver mutations across most cancer types and identify cancer type-specific subclonal patterns of driver gene mutations, fusions, structural variants, and copy number alterations as well as dynamic changes in mutational processes between subclonal expansions. Our results underline the importance of ITH and its drivers in tumor evolution and provide a pan-cancer resource of comprehensively annotated subclonal events from whole-genome sequencing data.

Liquid biopsy in NSCLC: a new challenge in radiation therapy

Lung cancer is the most common cancer and the leading cause of cancer mortality worldwide. To date, tissue biopsy has been the gold standard for the diagnosis and the identification of specific molecular mutations, to guide choice of therapy. However, this procedure has several limitations. Liquid biopsy could represent a solution to the intrinsic limits of traditional biopsy. It can detect cancer markers such as circulating tumor DNA or RNA (ctDNA, ctRNA), and circulating tumor cells, in plasma, serum or other biological fluids. This procedure is minimally invasive, reproducible and can be used repeatedly. The main clinical applications of liquid biopsy in non-small cell lung cancer (NSCLC) patients are the early diagnosis, stratification of the risk of relapse, identification of mutations to guide application of targeted therapy and the evaluation of the minimum residual disease. In this review, the current role of liquid biopsy and associated markers in the management of NSCLC patients was analyzed, with emphasis on ctDNA and CTCs, and radiotherapy.

Genomic heterogeneity and copy number variant burden are associated with poor recurrence-free survival and 11q loss in human papillomavirus-positive squamous cell carcinoma of the oropharynx

BACKGROUND

Human papillomavirus-positive (HPV+) squamous cell carcinoma of the oropharynx (OPSCC) is the most prevalent HPV-associated malignancy in the United States. Favorable treatment outcomes have led to increased interest in treatment de-escalation to reduce treatment morbidity as well as the development of prognostic markers to identify appropriately low-risk patients. Intratumoral genomic heterogeneity and copy number alteration burden have been demonstrated to be predictive of poor outcomes in many other cancers; therefore, we sought to determine whether intratumor heterogeneity and genomic instability are associated with poor outcomes in HPV+ OPSCC.

METHODS

Tumor heterogeneity estimates were made based on targeted exome sequencing of 45 patients with HPV+ OPSCC tumors. Analysis of an additional cohort of HPV+ OPSCC tumors lacking matched normal sequencing allowed copy number analysis of 99 patient tumors.

RESULTS

High intratumorally genomic heterogeneity and high numbers of copy number alterations were strongly associated with worse recurrence-free survival. Tumors with higher heterogeneity and frequent copy number alterations were associated with loss of distal 11q, which encodes key genes related to double-strand break repair, including ATM and MRE11A.

CONCLUSIONS

Both intratumor genomic heterogeneity and high-burden copy number alterations are strongly associated with poor recurrence-free survival in patients with HPV+ OPSCC. The drivers of genomic instability and heterogeneity in these tumors remains to be elucidated. However, 11q loss and defective DNA double-strand break repair have been associated with genomic instability in other solid tumors. Copy number alteration burden and intratumoral heterogeneity represent promising avenues for risk stratification of patients with HPV+OPSCC.

Stromal score as a prognostic factor in primary gastric cancer and close association with tumor immune microenvironment

Background

Gastric cancer remains one of the major causes for tumor‐related deaths worldwide. Our study aimed to provide an understanding of primary gastric cancer and prompt its clinical diagnosis and treatment.

Methods

We integrated the expression profiles and overall survival information of primary gastric cancer in TCGA and GEO database and estimated the stromal score of each sample by the estimate R package. Stromal score and clinicopathologic characteristics associated with overall survival were analyzed by using Cox regression and the Kaplan‐Meier method. Gene set enrichment analysis (GSEA) and KEGG analysis were performed to explore the potential molecular mechanism in TCGA dataset. The relationship between immunotherapy‐associated markers or immune cell types and stromal score was explored by using Pearson correlation analysis.

Results

A total of 796 samples were collected for the analysis. Patients with stromal score‐high showed poor overall survival (P < .01, HR: 1.407, 95% CI: 1.144‐1.731) and identified as an independent prognostic factor. KEGG analysis revealed that stromal score actively involved in diverse tumor‐associated pathways. GSEA analysis also revealed stromal score associated with diverse immune‐related biological processes. Furthermore, stromal score was related with immunotherapy‐associated markers and multiple immune cells.

Conclusion

Our results showed that stromal score could serve as a potential prognostic biomarker in primary gastric cancer and play an important role in the recognition, surveillance, and prognosis of gastric cancer.

The Effects of Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer-The Impact in Intratumoral Heterogeneity

Purpose: Intratumoral genetic heterogeneity (ITGH) is a common feature of solid tumors. However, little is known about the effect of neoadjuvant chemoradiation (nCRT) in ITGH of rectal tumors that exhibit poor response to nCRT. Here, we examined the impact of nCRT in the mutational profile and ITGH of rectal tumors and its adjacent irradiated normal mucosa in the setting of incomplete response to nCRT.

Methods and Materials: To evaluate ITGH in rectal tumors, we analyzed whole-exome sequencing (WES) data from 79 tumors obtained from The Cancer Genome Atlas (TCGA). We also compared matched peripheral blood cells, irradiated normal rectal mucosa and pre and post-treatment tumor samples (PRE-T and POS-T) from one individual to examine the iatrogenic effects of nCRT. Finally, we performed WES of 7 PRE-T/POST-T matched samples to examine how nCRT affects ITGH. ITGH was assessed by quantifying subclonal mutations within individual tumors using the Mutant-Allele Tumor Heterogeneity score (MATH score).

Results: Rectal tumors exhibit remarkable ITGH that is ultimately associated with disease stage (MATH score stage I/II 35.54 vs. stage III/IV 44.39, p = 0.047) and lymph node metastasis (MATH score N0 35.87 vs. N+ 45.79, p = 0.026). We also showed that nCRT does not seem to introduce detectable somatic mutations in the irradiated mucosa. Comparison of PRE-T and POST-T matched samples revealed a significant increase in ITGH in 5 out 7 patients and MATH scores were significantly higher after nCRT (median 41.7 vs. 28.8, p = 0.04). Finally, we were able to identify a subset of “enriched mutations” with significant changes in MAFs between PRE-T and POST-T samples. These “enriched mutations” were significantly more frequent in POST-T compared to PRE-T samples (92.9% vs. 7.1% p < 0.00001) and include mutations in genes associated with genetic instability and drug resistance in colorectal cancer, indicating the expansion of tumor cell subpopulations more prone to resist to nCRT.

Conclusions: nCRT increases ITGH and may result in the expansion of resistant tumor cell populations in residual tumors. The risk of introducing relevant somatic mutations in the adjacent mucosa is minimal but non-responsive tumors may have potentially worse biological behavior when compared to their untreated counterparts. This was an exploratory study, and due to the limited number of samples analyzed, our results need to be validated in larger cohorts.

Tumor Infiltrating Lymphocytes and Macrophages Improve Survival in Microsatellite Unstable Colorectal Cancer

Due to the loss of DNA repair mechanisms in colorectal cancer (CRC) with microsatellite instability (MSI), somatic mutations accumulate within DNA; making them more prone to attack by tumor infiltrating lymphocytes (TIL) and macrophages. We hypothesize that MSI-High (MSI-H) patients have favorable survival due to increased tumor immunogenicity. The Cancer Genome Atlas (TCGA) was used to evaluate gene expression from 283 patients with CRC, comparing MSI-H and microsatellite stable (MSS) patients. CIBERSORT algorithm estimated the fraction of immune cell types. We found that low expression of DNA repair genes (MLH1, MLH3, PMS1, PMS2, ATR, PRKDC, ATM, BRCA2) associated with MSI-H. MSI-H was directly associated with Helper T-cells (p = 0.034) and M1 macrophages (p < 0.0001). MSI-H tumors associated with diminished intra-tumoral heterogeneity as well as higher expression of checkpoint molecules PD-1, PD-L1, CTLA4, LAG3 and TIM3 (p < 0.0001). Improved OS was seen in patients with low ATM, PMS2 and MLH3. In the TCGA CRC cohort, decreased expression of DNA repair genes associated with MSI-H. MSI-H patients had improved survival, likely due to higher TIL and M1 macrophage infiltration as well as lower intra-tumoral heterogeneity. MSI-H also associates with expression of immune checkpoint molecules with potential for development of therapeutic targets.

Triple-Negative Breast Cancer with High Levels of Annexin A1 Expression Is Associated with Mast Cell Infiltration, Inflammation, and Angiogenesis

Annexin A1 (ANXA1) is a phospholipid-linked protein involved in inflammation, immune response, and mast cell reactivity. Recently, we reported that ANXA1 is associated with aggressive features of triple-negative breast cancer (TNBC); however, its clinical relevance remains controversial. We hypothesized that human TNBC with high expression of ANXA1 mRNA is associated with pro-cancerous immune cell infiltration, including mast cells, and with an aggressive phenotype. Clinical and RNA-seq data were obtained from The Cancer Genome Atlas (TCGA, n = 1079) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) (n = 1904). TNBC patients had significantly higher levels of ANXA1 expression compared to the other subtypes in both TCGA and METABRIC cohorts (p < 0.001). ANXA1 protein expression was assessed by immunohistochemistry in Japanese TNBC patient cohort (n = 48), where 17 cases (35.4%) had positive ANXA1 staining, and their overall survival was significantly shorter compared with negative staining group (p = 0.008). The CIBERSORT algorithm was used to calculate immune cell infiltrations. ANXA1 high tumors were associated with activated mast cells and M2 macrophages (p > 0.01), but did not show any association with tumor heterogeneity nor cytolytic activity. High expression of ANXA1 group enriched inflammation, epithelial-to-mesenchymal transition (EMT), and angiogenesis-related genes in a gene set enrichment assay in both cohorts. To our knowledge, this is the first study to demonstrate that ANXA1 is associated with infiltration of mast cells and inflammation that is associated with the aggressive phenotype of TNBC, such as EMT and angiogenesis.

Morphomolecular analysis of the immune tumor microenvironment in human head and neck cancer

Immunotherapy is effective in head and neck squamous cell carcinoma (HNSCC), but only a minority of patients responds to immune checkpoint blockade (ICB). To contribute to a better understanding of the underlying immune biology, we combined histomorphological evaluation and molecular analysis of the HNSCC immune microenvironment in the TCGA cohort. Analyzing digital HE-stained slides, a method for classification of tumor infiltrating lymphocytes (TILs) in the intra-epithelial compartment (ieTILs, present vs. absent) and the stromal compartment (strTILs, high vs. low) was established. We also analyzed the abundance of eight immune cell populations (estimated from RNAseq data) and PD-L1 mRNA expression. Status of ieTILs and status of strTILs were concordant for 61%, but discordant for 39% of tumors. In univariate survival analysis, ieTILs were a positive prognostic marker for DFS in the study cohort (HR = 0.66, p = 0.015) and in the HPV- subcohort (HR = 0.68, p = 0.04), but not in the HPV + subcohort. T cells were a positive prognostic marker for DFS in the study cohort (HR = 0.80, p = 0.03) and in the HPV + subcohort (HR = 0.20, p = 0.001), but not in the HPV- subcohort. In univariate survival analysis, PD-L1 mRNA expression was neither associated with DFS nor with OS. However, in bivariate and multivariate analyses including both PD-L1 mRNA levels and T cells, PD-L1 was a negative prognostic marker of DFS and OS, while T cells remained a positive prognostic marker. In conclusion, ieTILs and strTILs were non-redundant biomarkers in HNSCC and should be evaluated separately. The identified prognostic markers should be evaluated for predictivity in ICB-treated patients.

Is high-risk cutaneous squamous cell carcinoma of the head and neck a suitable candidate for current targeted therapies?

OBJECTIVE

Cutaneous squamous cell carcinoma (cSCC) is the second most common malignancy, most frequently affecting the head and neck. Treatment often requires surgery and can have significant functional morbidity. Research into disease pathogenesis and second line medical management of cSCC is limited. We assess genetic mutations in high-risk, primary head and neck cutaneous squamous cell carcinomas (HNcSCC) that may hinder or be beneficial for use of targeted therapy in disease management.

METHODS

Genetic alterations and variant allele frequencies (VAFs) were analysed using a clinically relevant 48 gene panel in 10 primary high-risk non-metastatic treatment-naïve HNcSCC to evaluate applicability of targeted therapeutics. Variants present at all VAFs were evaluated for pathogenicity. Somatic mutation patterns of individual tumours were analysed.

RESULTS

High-risk HNcSCC showed a high proportion (82%) of C to T transitions in keeping with ultraviolet-mediated damage. There was significant intratumour genetic heterogeneity in this cohort (MATH scores 20-89) with the two patients <45 years of age showing highest intratumour heterogeneity. TP53 was altered at VAF >22% in all cases, and mutations with highest VAF were observed in tumour suppressor genes in 80%. 70% of cases demonstrated at least one mutation associated with treatment resistance (KIT S821F, KIT T670I, RAS mutations at codons 12 and 13).

CONCLUSION

We demonstrate high proportion tumour suppressor loss of function mutations, high intratumour genetic heterogeneity, and presence of well recognised resistance mutations in treatment naïve primary HNcSCC. These factors pose challenges for successful utilisation of targeted therapies.

Estrogen Receptor Positive Breast Cancer with High Expression of Androgen Receptor has Less Cytolytic Activity and Worse Response to Neoadjuvant Chemotherapy but Better Survival

Estrogen receptor (ER) positive breast cancer (BC), the most abundant BC subtype, is notorious for poor response to neoadjuvant chemotherapy (NAC). The androgen receptor (AR) was reported to support estradiol-mediated ER activity in an in vitro system. Recently, ER-positive BC with fewer tumor infiltrating lymphocytes (TILs) was shown to have a better prognosis, opposite to the trend seen with ER-negative BC. We hypothesized that ER-positive BC with high expression of AR will have fewer TILs and an inferior response to NAC, but with a better prognosis. In both TCGA and METABRIC cohorts, AR expression was significantly higher in ER-positive BCs compared to ER-negatives (p < 0.001, p < 0.001, respectively) and it correlated with ER expression (R = 0.630, R = 0.509, respectively). In ER-positive tumors, AR high tumors enriched UV response down (NES = 2.01, p < 0.001), and AR low tumors enriched DNA repair (NES = −2.02, p < 0.001). AR high tumors were significantly associated with procancer regulatory T-cells, and AR low tumors were associated with anticancer immune cells, such as CD4, CD8, and Gamma-Delta T-cells and memory B-cells in ER-positive BC (p < 0.01). Further, cytolytic activity was significantly lower in AR high BC in both cohorts. Finally, AR high tumors had a significantly lower rate of attaining pathological complete response to NAC (GSE22358), but better survival. In conclusion, our results demonstrated that high AR has fewer tumor infiltrating lymphocytes as well as cytolytic activity and an inferior response to NAC, but better survival in ER-positive BC.

Tumor Heterogeneity Correlates with Less Immune Response and Worse Survival in Breast Cancer Patients

BACKGROUND

Intratumor heterogeneity implies that subpopulations of cancer cells that differ in genetic, phenotypic, or behavioral characteristics coexist in a single tumor (Ma in Breast Cancer Res Treat 162(1):39-48, 2017; Martelotto in Breast Cancer Res 16(3):210, 2014). Tumor heterogeneity drives progression, metastasis and treatment resistance, but its relationship with tumor infiltrating immune cells is a matter of debate, where some argue that tumors with high heterogeneity may generate neoantigens that attract immune cells, and others claim that immune cells provide selection pressure that shapes tumor heterogeneity (McGranahan et al. in Science 351(6280):1463-1469, 2016; McGranahan and Swanton in Cell 168(4):613-628, 2017). We sought to study the association between tumor heterogeneity and immune cells in a real-world cohort utilizing The Cancer Genome Atlas.

METHODS

Mutant allele tumor heterogeneity (MATH) was calculated to estimate intratumoral heterogeneity, and immune cell compositions were estimated using CIBERSORT. Survival analyses were demonstrated using Kaplan-Meir curves.

RESULTS

Tumors with high heterogeneity (high MATH) were associated with worse overall survival (p = 0.049), as well as estrogen receptor-positive (p = 0.011) and non-triple-negative tumors (p = 0.01). High MATH tumors were also associated with less infiltration of anti-tumor CD8 (p < 0.013) and CD4 T cells (p < 0.00024), more tumor-promoting regulatory T cells (p < 4e-04), lower expression of T-cell exhaustion markers, specifically PDL-1 (p = 0.0031), IDO2 (p = 0.34), ADORA2A (p = 0.018), VISTA (p = 0.00013), and CCR4 (p < 0.00001), lower expression of cytolytic enzymes granzyme A (p = 0.0056) and perforin 1 (p = 0.053), and low cytolytic activity score (p = 0.0028).

CONCLUSIONS

High heterogeneity tumors are associated with less immune cell infiltration, less activation of the immune response, and worse survival in breast cancer. Our results support the notion that tumor heterogeneity is shaped by selection pressure of tumor-infiltrating immune cells.

Translating insights into tumor evolution to clinical practice: promises and challenges

Accelerating technological advances have allowed the widespread genomic profiling of tumors. As yet, however, the vast catalogues of mutations that have been identified have made only a modest impact on clinical medicine. Massively parallel sequencing has informed our understanding of the genetic evolution and heterogeneity of cancers, allowing us to place these mutational catalogues into a meaningful context. Here, we review the methods used to measure tumor evolution and heterogeneity, and the potential and challenges for translating the insights gained to achieve clinical impact for cancer therapy, monitoring, early detection, risk stratification, and prevention. We discuss how tumor evolution can guide cancer therapy by targeting clonal and subclonal mutations both individually and in combination. Circulating tumor DNA and circulating tumor cells can be leveraged for monitoring the efficacy of therapy and for tracking the emergence of resistant subclones. The evolutionary history of tumors can be deduced for late-stage cancers, either directly by sampling precursor lesions or by leveraging computational approaches to infer the timing of driver events. This approach can identify recurrent early driver mutations that represent promising avenues for future early detection strategies. Emerging evidence suggests that mutational processes and complex clonal dynamics are active even in normal development and aging. This will make discriminating developing malignant neoplasms from normal aging cell lineages a challenge. Furthermore, insight into signatures of mutational processes that are active early in tumor evolution may allow the development of cancer-prevention approaches. Research and clinical studies that incorporate an appreciation of the complex evolutionary patterns in tumors will not only produce more meaningful genomic data, but also better exploit the vulnerabilities of cancer, resulting in improved treatment outcomes.

Intratumor genetic heterogeneity in squamous cell carcinoma of the oral cavity

BACKGROUND

We sought to evaluate intratumor heterogeneity in squamous cell carcinoma of the oral cavity (OCC) and specifically determine the effect of physical separation and histologic differentiation within the same tumor.

METHODS

We performed whole exome sequencing on five biopsy sites-two from well-differentiated, two from poorly differentiated regions, and one from normal parenchyma-from five primary OCC specimens.

RESULTS

We found high levels of intratumor heterogeneity and, in four primary tumors, identified only 0 to 2 identical mutations in all subsites. We found that the heterogeneity inversely correlated with physical separation and that pairs of well-differentiated samples were more similar to each other than analogous poorly differentiated specimens. Only TP53 mutations, but not other purported "driver mutations" in head and neck squamous cell carcinoma, were found in multiple biopsy sites.

CONCLUSION

These data highlight the challenges to characterization of the mutational landscape of OCC with single site biopsy and have implications for personalized medicine.

Tumor Heterogeneity as a Predictor of Response to Neoadjuvant Chemotherapy in Locally Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) is the standard of care for locally advanced adenocarcinoma of the rectum, but it is currently unknown which patients have disease that will respond. This study tested the correlation between response to nCRT and intratumoral heterogeneity using next-generation sequencing assays.

PATIENTS AND METHODS

DNA was extracted from formalin-fixed, paraffin-embedded biopsy samples from a cohort of patients with locally advanced rectal adenocarcinoma (T3/4 or N1/2 disease) who received nCRT. High read-depth sequencing of > 400 cancer-relevant genes was performed. Tumor mutations and variant allele frequencies were used to calculate mutant-allele tumor heterogeneity (MATH) scores as measures of intratumoral heterogeneity. Response to nCRT was pathologically scored after surgical resection.

RESULTS

Biopsy samples from 21 patient tumors were analyzed. Eight patients had disease noted to have complete response, 2 moderate, 4 minimal, and 7 poor. Higher MATH scores correlated with poorer response to treatment, demonstrating significantly increased tumor heterogeneity compared to complete response (P = .039).

CONCLUSION

The application of MATH scores as a measure of tumor heterogeneity may provide a useful biomarker for treatment response in locally advanced rectal cancer.

Integrated analysis of the immunological and genetic status in and across cancer types: impact of mutational signatures beyond tumor mutational burden

Harnessing the immune system by checkpoint blockade has greatly expanded the therapeutic options for advanced cancer. Since the efficacy of immunotherapies is influenced by the molecular make-up of the tumor and its crosstalk with the immune system, comprehensive analysis of genetic and immunologic tumor characteristics is essential to gain insight into mechanisms of therapy response and resistance. We investigated the association of immune cell contexture and tumor genetics including tumor mutational burden (TMB), copy number alteration (CNA) load, mutant allele heterogeneity (MATH) and specific mutational signatures (MutSigs) using TCGA data of 5722 tumor samples from 21 cancer types. Among all genetic variables, MutSigs associated with DNA repair deficiency and AID/APOBEC gene activity showed the strongest positive correlations with immune parameters. For smoking-related and UV-light-exposure associated MutSigs a few positive correlations were identified, while MutSig 1 (clock-like process) correlated non-significantly or negatively with the major immune parameters in most cancer types. High TMB was associated with high immune cell infiltrates in some but not all cancer types, in contrast, high CNA load and high MATH were mostly associated with low immune cell infiltrates. While a bi- or multimodal distribution of TMB was observed in colorectal, stomach and endometrial cancer where its levels were associated with POLE/POLD1 mutations and MSI status, TMB was unimodal distributed in the most other cancer types including NSCLC and melanoma. In summary, this study uncovered specific genetic-immunology associations in major cancer types and suggests that mutational signatures should be further investigated as interesting candidates for response prediction beyond TMB.

Mutant-allele fraction heterogeneity is associated with non-small cell lung cancer patient survival

Genetic intratumor heterogeneity is associated with tumor occurrence, development and overall outcome. The present study aims to explore the association between mutant-allele fraction (MAF) heterogeneity and patient overall survival in lung cancer. Somatic mutation data of 939 non-small cell lung cancer (NSCLC) cases were obtained from The Cancer Genome Atlas. Entropy-based mutation allele fraction (EMAF) score was used to describe the uncertainty of individual somatic mutation patterns and to further analyze the association with patient overall survival. Results indicated that association between EMAF and overall survival was significant in the discovery set [hazard ratio (H)R=1.62; 95% confidence interval (CI): 1.08–2.41; P=0.018] and replication set (HR=1.63; 95% CI: 1.11–2.37; P=0.011). In addition, EMAF was also significantly different in lung adenocarcinoma and squamous cell carcinoma. Furthermore, a significant difference was indicated in early-stage patients. Results from c-index analysis indicated that EMAF improved the model predictive performance on the 3-year survival beyond that of traditional clinical staging, particularly in early-stage patients. In conclusion, EMAF successfully reflected MAF heterogeneity among patients with NSCLC. Additionally, EMAF improved the predictive performance in early-stage patient prognosis beyond that of traditional clinical staging. In clinical application, EMAF appears to identify a subset of early-stage patients with a poor prognosis and therefore may help inform clinical decisions regarding the application of chemotherapy after surgery.

Gender-related prognostic value and genomic pattern of intra-tumor heterogeneity in colorectal cancer

Intra-tumor heterogeneity (ITH) is crucial in tumorigenesis and resistance to target therapy. Here, we used mutant-allele tumor heterogeneity (MATH) to measure ITH based on next-generation sequencing data and high MATH was proven as an independent risk prognostic factor in male CRC patients in both a training set of 284 colorectal cancer (CRC) patients with from The Cancer Genome Atlas (TCGA) and a validating set of 187 CRC patients from International Cancer Genome Consortium (ICGC). Further, the genomic pattern according to MATH demonstrated that mutation rates of TP53, IRF5 and KRAS were independently associated with MATH, and the latter two were only significant in male patients. As MATH increased, the fraction of somatic copy number alteration (SCNA) elevated. Moreover, more SCNA events was independently associated with MATH in male than in female. WNT pathway, TGF-β pathway and DNA repair deficiency was enriched in high MATH group and the latter two showed up only in male patients. In summary, we reveal the gender-related prognostic value of MATH and relevant genomic pattern in CRC. Potential mechanisms are provided and it remains to be proven whether they are drivers of subclone formation and ITH. Taking MATH into consideration in clinical trial might contribute to better therapeutic strategies in CRC with researches added on in the future.

Maintenance of head and neck tumor on-chip: gateway to personalized treatment?

AIM

Head and neck squamous cell carcinomas (HNSCC) are solid tumors with low overall survival (40-60%). In a move toward personalized medicine, maintenance of tumor biopsies in microfluidic tissue culture devices is being developed.

METHODOLOGY/RESULTS

HNSCC (n = 15) was dissected (5-10 mg) and either analyzed immediately or cultured in a microfluidic device (37°C) for 48 h. No difference was observed in morphology between pre- and postculture specimens. Dissociated samples were analyzed using trypan blue exclusion (viability), propidium iodide flow cytometry (death) and MTS assay (proliferation) with no significant difference observed highlighting tissue maintenance. Computational fluid dynamics showed laminar flow within the system.

CONCLUSION

The microfluidic culture system successfully maintained HNSCC for 48 h, the culture system will allow testing of different treatment modalities with response monitoring.

Moving towards personalised therapy in head and neck squamous cell carcinoma through analysis of next generation sequencing data

Personalised medicine tumour boards, which leverage genomic data to improve clinical management, are becoming standard for the treatment of many cancers. This paper is designed as a primer to assist clinicians treating head and neck squamous cell carcinoma (HNSCC) patients with an understanding of the discovery and functional impact of recurrent genetic lesions that are likely to influence the management of this disease in the near future. This manuscript integrates genetic data from publicly available array comparative genome hybridization (aCGH) and next-generation sequencing genetics databases to identify the most common molecular alterations in HNSCC. The importance of these genetic discoveries is reviewed and how they may be incorporated into clinical care decisions is discussed. Considerations for the role of genetic stratification in the clinical management of head and neck cancer are maturing rapidly and can be improved by integrating data sets. This article is meant to summarise the discoveries made using multiple genomic platforms so that the head and neck cancer care provider can apply these discoveries to improve clinical care.

The Tip of the Iceberg: Clinical Implications of Genomic Sequencing Projects in Head and Neck Cancer

Recent genomic sequencing studies have provided valuable insight into genetic aberrations in head and neck squamous cell carcinoma. Despite these great advances, certain hurdles exist in translating genomic findings to clinical care. Further correlation of genetic findings to clinical outcomes, additional analyses of subgroups of head and neck cancers and follow-up investigation into genetic heterogeneity are needed. While the development of targeted therapy trials is of key importance, numerous challenges exist in establishing and optimizing such programs. This review discusses potential upcoming steps for further genetic evaluation of head and neck cancers and implementation of genetic findings into precision medicine trials.

Molecular Aspects of Head and Neck Cancer Therapy

In spite of a rapidly expanding understanding of head and neck tumor biology and optimization of radiation, chemotherapy, and surgical treatment modalities, head and neck squamous cell carcinoma (HNSCC) remains a major cause of cancer-related morbidity and mortality. Although our biologic understanding of these tumors had largely been limited to pathways driving proliferation, survival, and differentiation, the identification of HPV as a major driver of HNSCC and genomic sequencing analyses has dramatically influenced our understanding of tumor biology and approach to therapy. Here, we summarize molecular aspects of HNSCC biology and identify promising areas for potential diagnostic and therapeutic agents.