Oral cancer is one of the most common malignancies in the world that has been a significant health challenge across the world. Although there have been improvements in dental medicine, the progress of the patients seems to greatly depend on the level where the disease is spotted. The diagnosis must be done early so that it can be treated successfully, however, the conventional methods of diagnosis including the physical examination and biopsy, only allow the diagnosis to be made when the disease is already at its visible or symptomatic stage.
As molecular biology tools have become a reality, scientists and clinicians are changing the process of detecting, monitoring, and treating oral cancer. Polymerase chain reaction (PCR), gene expression profiling, and proteomics are some of the techniques that have provided novel opportunities to determine cancer at the molecular level-way before clinical symptoms occur.
This article presents the most important molecular procedures that have promoted the advancement in the area of oral cancer detection and treatment and the way in which it assists in early diagnosis and customized treatment to enhance the outcome of the patients.
Fundamentals of Oral Cancer: The Molecular Dimension
Oral cancer mainly entails malignant development of tissues of the mouth cavity such as tongue, lips, gums and throat. The disease is usually acquired on the basis of a precancerous lesion that is subject to genetic and molecular alterations to produce uncontrolled cell growth.
At the molecular scale, oral cancer development is linked with the change of the oncogenes, tumor suppressor genes, and signal pathways which control the proliferation and apoptosis of cells. Determining these changes cannot be done without sophisticated molecular biology methods, which have the capability of identifying genetic mutations, abnormal expression of RNAs, and changes in protein profiles within a cell or tissues.
Molecular versus Traditional Diagnosis Paradigm Shift
Traditional diagnostic techniques used in detecting oral cancer e.g. visual examination, palpation, and histopathological analysis are useful but not very sensitive. Such methods can only spot cancer in cases of lesions that are clinically noticeable or invasive.
Conversely, molecular diagnostics enables clinicians to detect malignancy biomarkers in DNA, RNA and protein terms. Even in non-invasive biological samples, such as saliva, blood or cells exfoliated by the mouth, such tools can identify genetic mutations or aberrant expression patterns.
Through the incorporation of molecular techniques into clinical workflow, healthcare providers have now been in a position to screen persons at risk and identify cancer at its earliest and most curable stages. To get a comprehensive insight into the way in which oral cancer screening is done, visit this oral cancer screening guide.
Major Molecular Biology Applications in the Research and Diagnosis of Oral Cancer
Polymerase Chain Reaction (PCR)
Polymerase Chain Reaction (PCR) is a fundamental molecular biology technology that is used to multiply specific nucleic acid fragments, which can be used to measure the presence of small amounts of genetic material. PCR is used in the diagnostics of oral cancer to detect genetic mutation, viral oncogenes and methylation pattern associated with tumor development.
a. Oncogenic Viruses Detection
Risk factors of oral cancer are human papillomavirus (HPV) and Epstein-Bar virus (EBV) infections. Assays by PCR may be used to identify the presence of viral DNA in saliva or oral tissue samples, and this is a non-invasive technique of early screening.
b. Gene Mutation Analysis
Tumor suppressor (TP53, CDKN2A (p16)) and oncogenes (RAS) mutations are commonly seen in oral squamous cell carcinoma (OSCC). Clinicians can determine the presence and the level of expression of such important genes utilizing PCR and its variations like real time quantitative PCR (qPCR).
c. DNA Methylation Studies
Cancer is characterized with aberrant DNA methylation. Hypermethylation of promoter regions of cell cycle regulatory genes is assessed using Methylation-specific PCR (MSP) that enables the detection of cancer at an early stage and assessment of prognosis.
Gene Expression Profiling
The gene expression profiling is a high-throughput method that analyzes RNA expression patterns in the tissues. It offers useful knowledge on how genes are up- or down-regulated in the process of cancer development.
a. Microarray Technology
Profiling with microarrays facilitates the analysis of thousands of genes at once. Microarrays have been used in oral cancer to determine certain gene signatures including EGFR, MMP9, and VEGF overexpression which are associated with aggressiveness and metastasis of tumors.
b. RNA Sequencing (RNA-Seq)
RNA-Seq is a next-generation sequencing technique that gives a more accurate and quantitative transcriptomic change image. It assists in the detection of new biomarkers and fusion genes in tumorigenesis.
c. Clinical Applications
Diagnostic panels based on gene expression profiles are currently being incorporated into the precancer diagnosis. Additionally, the profiles are capable of forecasting the reaction of a patient to chemotherapy or targeted therapy, which lead to personalized medicine.
Proteomics: Cancer Proteome Mapping
Proteomics can be defined as a large-scale study of proteins and their interactions in cells. As proteins are involved in the majority of cellular functions, changes in proteins can be more informative of both disease states than genetic mutation alone.
a. Proteomics on Mass Spectrometry
Such methods as LC-MS/MS (liquid chromatography-tandem mass spectrometry) can be used to identify and determine the concentration of thousands of proteins in cancerous and healthy tissues. Proteomic analysis in oral cancer has detected overexpressed proteins which include annexins, heat shock proteins, and cytokeratins- possible biomarkers of early cancer diagnosis.
b. Saliva Proteomics
Saliva is an available and non-invasive diagnostic fluid. Salivarial proteomic analysis is capable of identifying altered protein signatures of oral cancer thus this method is the most suitable in terms of screening and monitoring of an entire population.
c. Therapeutic Target Identification
Proteomics helps in the identification of new therapeutic targets by exposing proteins that are linked to tumor growth, angiogenesis and metastasis. It is possible to then design drugs to block these critical proteins resulting in more effective treatment options.
Emerging Molecular Tools and Techniques
In addition to PCR, gene profiling, and proteomics, there are a number of new molecular techniques improving the accuracy of oral cancer studies:
Next-Generation Sequencing (NGS)
NGS allows a comprehensive analysis of the genome of tumors, determining somatic mutations, copy number changes, and changes in epigenetics. The technology is useful to classify oral cancers according to molecular subtypes, enhancing the prognostic accuracy and choice of treatment.
Liquid Biopsy
The liquid biopsy examines the circulating tumor DNA (ctDNA) and exosomes of blood or saliva. It provides a non-invasive method of monitoring tumor recurrence as well as treatment response in real time.
CRISPR-Based Diagnostics
Molecular detection CRISPR-Cas systems are traditionally used to edit genes but are now being adapted to detect genes. Assays based on CRISPR have the capacity to detect a tumor-specific sequence of nucleic acid with an unprecedented sensitivity, and can thus be used to diagnose them ultra-early.
Metabolomics
Metabolomics is the study of biochemical by-products of cellular metabolism. The metabolic reprogramming of oral cancer can be detected through altered metabolite levels in the saliva or serum, which is another way of obtaining molecular elements of the disease.
Molecular Biomarkers: The Future of Personalised Oral Cancer Care
As indicators of biological processes or disease states, molecular biomarkers, which can be genes, RNA transcripts, proteins or metabolites, can be measured. Their discovery and authenticity are changing the way oral cancer is handled in a number of ways:
Early Detection
Such markers as p53 mutations and EGFR overexpression and DNA methylation patterns may also indicate precancerous alterations before lesions develop.
Prognostic Assessment
Gene expression signature assists in differentiating between aggressive and attenuated types of oral cancer to enable clinicians to modify monitoring and treatment levels.
Targeted Therapy
Tumor-specific (targeted) drugs, e.g., EGFR or immune checkpoint, can be used with individual tumor profiles based on molecular information and have minimal toxicity, which maximizes activity.
Treatment Monitoring
Monitoring of tumors responding to treatment in real-time with the tracking of molecular modifications using either PCR or liquid biopsy can enhance adaptive treatment regimens.
Application of Molecular Tools in Clinical Practice
Despite the enormous potential of molecular diagnostics, it is necessary to overcome numerous barriers in order to establish the methods in everyday dental and medical care- this includes cost, technical skills, and regulatory approval.
However, personalized oral cancer treatment is becoming a reality due to interdisciplinary co-operation between molecular biologists, oncologists, and dental practitioners. The use of standardized molecular assays in the detection of biomarkers and treatment monitoring are increasingly becoming common in clinical laboratories.
Moreover, international programs are aiding in building molecular databases and AI-based interpreters to enhance the accuracy of a diagnosis.
Economic and Ethical Issues
The use of molecular diagnostics, like any advanced technology, has both ethical and economic issues. Genetic testing demands high levels of privacy in order to defend patient information. Also, the problem of access is also important- especially in low-resource areas where oral cancer is widespread.
There are still attempts to create inexpensive and fast molecular tests that can be used in large-scale screening in developing countries and provide equal access to healthcare.
The Future: In the Future of Oral Oncology: Precision Medicine
The interdisciplinary approach between the field of genomics, proteomics and bioinformatics is driving the field of oral cancer management towards a paradigm of precision medicine-a paradigm that customizes the diagnosis and treatment based on the individual molecular and genetic profile of the patient.
Chairside molecular diagnostic tools would also enable dentists to identify oral cancer biomarkers as part of their routine examination in the near future. Together with AI-based data analysis, these innovations will enhance the rate of early detection and survival of patients significantly.
Conclusion
A molecular revolution is taking place in the field of oral oncology. Beyond histological observations, tools such as PCR, gene expression profiling, and proteomics have greatly increased our understanding of the disease. In addition to facilitating the early detection of cancers, these molecular biology tools aid in the creation of customized treatments that improve therapeutic results and lessen adverse effects.
One molecule at a time, the goal of personalized, predictive, and preventive oral cancer care is coming closer to reality as research into these technologies advances.
