|LETTER TO EDITOR
|Year : 2014 | Volume
| Issue : 3 | Page : 377-378
Multiple head and neck carcinomas are of independent or common clonal origin?
Department of Oral and Maxillofacial Pathology and Microbiology, I. T. S. Center for Dental Studies and Research, Muradnagar, Ghaziabad, U.P., India
|Date of Web Publication||10-Dec-2014|
Dr. K Kumar
Department of Oral and Maxillofacial Pathology and Microbiology, I. T. S. Center for Dental Studies and Research, Muradnagar, Ghaziabad, U.P.
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kumar K. Multiple head and neck carcinomas are of independent or common clonal origin?. Indian J Cancer 2014;51:377-8
To explain the clonal relationship between the multiple primary tumors of the oral cavity, Slaughter et al. proposed the theory of "field cancerization" whereby multiple tumors could originate independently in an area of epithelium preconditioned to cancer development by long-term exposure to carcinogens. Initial molecular studies showing discordant p53 mutation between index and second primary cancers in head and neck seemed to support this theory of independent tumor origins. The recent concept of common clonal origin in multiple carcinomas of head and neck has gained support as a result of the detection of identical genetic alteration in these cancers. 
The p53 mutations may not be the earliest genetic change and there is a possibility that other genetic alteration may have occurred prior to the acquisition of p53 point mutations. So, the demonstration of different p53 mutation pattern does not necessarily exclude a clonal relationship between multiple head and neck carcinomas. To know whether tumors are of independent or common clonal origin requires determination of whether separate tumors have developed along similar or disparate genetic pathways. To analyze this, many authors focused on early genetic events, which conceivably occur before the migration of cells forming tumors of common clonal origin.
Many molecular techniques have been performed to identify the clonal relationship in multiple primary squamous cell carcinomas of head and neck region. , These techniques include karyotypic analysis, X-chromosome inactivation assay, fluorescence in situ hybridization (FISH), and microsatellite alteration analysis. , In most of these studies, a significant proportion of multiple synchronous and recurrent lesions appear to be clonally related, supporting the idea of local clonal spread. 
These studies help to explain the high incidence of recurrent squamous cell carcinomas of head and neck region despite excision or other therapy, as premalignant and malignant clone of cells often have the ability to migrate and persist outside of the field of treatment. Therefore, alternative means of prevention or therapy that can affect the entire head and neck region may be of benefit to such patients.
| » References|| |
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