GENESIS OF ORAL CANCER AND TECHNIQUES TO AMELIORATE IT

Oral squamous cell carcinoma(SCC) is a debilitating and lethal disease with increasing incidence (more than 90% of all oral cancers) and low survival rates for past 3 decades in developed as well as developing countries. The poor prognosis for SCC patients may be a reflection of the fact that while many of the risk factors involved in SCC pathogenesis, such as alcohol and tobacco, are well-recognized, by contrast very little is known about the molecular mechanisms responsible for this type of cancer. Latest innovative techniques like laser capture microdissection, comparative genomic hybridization, microarrays, and protein chips etc. have revolutionized the study of  molecular blueprint for SCC, thus helping to identify suitable markers for the early detection of pre neoplastic lesions, as well as novel targets for pharmacological intervention in this disease as various pharma companies and cancer institutes are on a hunt for anti-cancer drug. These revolutionary approaches and the new breed of oncologists have made the field very exciting and have generated the hope that finally the war against cancer would be won.

Each year, thousands of deaths are attributed to cancers of the oral cavity, salivary glands, larynx, and pharynx. Since more than 90% of these neoplastic lesions are of squamous cell origin, they are usually referred to, collectively, as squamous cell carcinomas of the head and neck (HNSCC). Oral squamous cell carcinoma (OSCC) is the most common malignant disease of the oral and maxillo-facial region, and the sixth most frequent cancer worldwide.

The poor prognosis for HNSCC patients may be a reflection of the fact that while many of the risk factors involved in HNSCC pathogenesis, such as alcohol and tobacco, are well-recognized by contrast very little is known about the molecular mechanisms responsible for this type of cancer.

Recent discoveries have dramatically increased our understanding of the most basic mechanisms controlling normal cell growth, and have also greatly enhanced our ability to investigate the nature of the biological processes that lead to cancer. We now know that the majority of cells in a tumor derive from the clonal expansion of a single ancestral cell that has acquired an aberrant program of cell growth. Whereas normal cells proliferate only when needed, as a result of a delicate balance between growth promoting and growth-inhibiting factors and under the influence of biochemical cues provided by neighboring cells, cancer cells override these controlling mechanisms and follow their own internal program for timing their reproduction. These cells usually grow in an unrestricted manner, and over the time they can acquire the ability to migrate from their original site, invade nearby tissues, and metastasize at distant anatomical sites.

Past few years have seen a tremendous increase in our understanding of the basic mechanisms controlling normal and aberrant cell growth, particularly of those molecular processes that may be responsible for the acquisition of the transformed and metastatic phenotype. 

Parallel to this, there has been a flood of information from sequencing efforts and chip-based assays, and this has resulted in the establishment of large public databases. Recent advances in computational technology and the development of powerful search engines and highly sophisticated bioinformatics tools will facilitate the analysis of this large body of information, thus providing investigators with an unique opportunity to use this knowledge to address biologically relevant questions.

With this readily available technology and information, it will soon be possible to translate all DNA sequences into amino acids and ascribe functions to most of the newly discovered genes. Until very recently, investigators studied the molecular biology of cancer by concentrating all efforts on one or a few genes at a time. However, recent advances in DNA sequencing and microarray technologies, among others, have provided a unique opportunity for thousands of genes to be monitored simultaneously.

The use of these technologies therefore allows for the scanning of gene expression patterns and the search for those correlating with a disease state. It can be concluded that exciting opportunities are ahead for our understanding of the molecular basis of oral and pharyngeal cancers. However, it is becoming increasingly clear that it will take a concerted effort from the entire scientific and health professional community to battle the ravaging consequences of this disease.