Identification of Prognostic Biomarkers Originating From the Tumor Stroma of Betel Quid-Associated Oral Cancer Tissues

Abstract

BackgroundPartial epithelial-mesenchymal transition (p-EMT) is a distinct clinicopathological feature prevalent in oral cavity tumors of The Cancer Genome Atlas. Located at the invasion front, p-EMT cells require additional support from the tumor stroma for collective cell migration, including track clearing, extracellular matrix remodeling and immune evasion. The pathological roles of otherwise nonmalignant cancer-associated fibroblasts (CAFs) in cancer progression are emerging.MethodsGene set enrichment analysis was used to reveal differentially enriched genes and molecular pathways in OC3 and TW2.6 xenograft tissues, representing mesenchymal and p-EMT tumors, respectively. R packages of genomic data science were executed for statistical evaluations and data visualization. Immunohistochemistry and Alcian blue staining were conducted to validate the bioinformatic results. Univariate and multivariate Cox proportional hazards models were performed to identify covariates significantly associated with overall survival in clinical datasets. Kaplan–Meier curves of estimated overall survival were compared for statistical difference using the log-rank test.ResultsCompared to mesenchymal OC3 cells, tumor stroma derived from p-EMT TW2.6 cells was significantly enriched in microvessel density, tumor-excluded macrophages, inflammatory CAFs, and extracellular hyaluronan deposition. By translating these results to clinical transcriptomic datasets of oral cancer specimens, including the Puram single-cell RNA-seq cohort comprising ~6000 cells, we identified the expression of stromal TGFBI and HYAL1 as independent poor and protective biomarkers, respectively, for 40 Taiwanese oral cancer tissues that were all derived from betel quid users. In The Cancer Genome Atlas, TGFBI was a poor marker not only for head and neck cancer but also for additional six cancer types and HYAL1 was a good indicator for four tumor cohorts, suggesting common stromal effects existing in different cancer types.ConclusionsAs the tumor stroma coevolves with cancer progression, the cellular origins of molecular markers identified from conventional whole tissue mRNA-based analyses should be cautiously interpreted. By incorporating disease-matched xenograft tissue and single-cell RNA-seq results, we suggested that TGFBI and HYAL1, primarily expressed by stromal CAFs and endothelial cells, respectively, could serve as robust prognostic biomarkers for oral cancer control.

Developments and future prospects of personalized medicine in head and neck squamous cell carcinoma diagnoses and treatments

“…Examination of miRNAs in plasma samples from tumors and controls demonstrated an up‐regulation of various miRNAs, including miR‐24, miR‐181, miR‐196a, miR‐10b, miR‐187*, in OSCC tissues and plasma compared to control samples. 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 Additionally, elevated expression of miR‐155 was observed in tissue and plasma samples of LSCC compared to controls. 86 , 87 Conversely, reduced expression of miR‐497 was noted in tissue and plasma of nasopharyngeal carcinoma (NPC) patients relative to noncancerous control patients' plasma.…”

“…Examination of miRNAs in plasma samples from tumors and controls demonstrated an up‐regulation of various miRNAs, including miR‐24, miR‐181, miR‐196a, miR‐10b, miR‐187*, in OSCC tissues and plasma compared to control samples 77–85 . Additionally, elevated expression of miR‐155 was observed in tissue and plasma samples of LSCC compared to controls 86,87 .…”

Precancerous Lesions of the Head and Neck Region and Their Stromal Aberrations: Piecemeal Data

“…In the same vein, Liu et al used seven existing RNA expression datasets from a broad spectrum of cancers to define CAF populations. From their analysis, three main fibroblast populations crystalized, i.e., CAF1/myCAF (markers PDPN, FN1), CAF2/iCAF, and myofibroblasts [ 37 ]. Taken together, these data suggest that there could be an overemphasis on ACTA2-positive “CAFs,” and one can boil down CAFs to two main subtypes which do not exist in PMDs.…”

The Way to Malignant Transformation: Can Epigenetic Alterations Be Used to Diagnose Early-Stage Head and Neck Cancer?

“…In our experiments, p-EMT but not mesenchymal cells exhibited multicellular cohesiveness and spheroid invasion in vitro, as well as collective angiolymphatic and perineural invasions in an immunodeficient mouse model [ 40 ]. Integrated transcriptomic analysis of xenograft tissues revealed that p-EMT and mesenchymal cells coexisted with different subtypes of host cancer-associated fibroblasts (CAFs): inflammatory and myofibroblastic CAFs, respectively [ 41 , 42 ]. Thus, our data support the hypothesis that tumor and stromal cells might influence each other through epigenetically driven cellular plasticity and coevolve to form an ecosystem [ 37 ].…”