Apr 4, 2012Science and Technology
New method for detecting oral cancer

Oral squamous cell carcinoma cells have genetic underpinnings that have now been identified.Ninety percent of head and neck cancer cases are due to squamous cell carcinoma -- a cancer of the epithelial cells.  Oral squamous cell carcinoma (OSCC) affects 270,000 people worldwide every year, and may present as tumors on the tongue or gingiva (gums).  External risk factors, such as smoking and alcohol consumption, are well known to cause OSCC, but the underlying genetic origins have remained a mystery.  Scientists at the National University Corporation Tokyo Medical and Dental University discovered the causative gene for OSCC, and hope to apply this knowledge to establishing strategic understanding for effective therapeutic methods and prevention.

It is well known that cancer is caused by mutations in the proteins of the affected cells.  Research initially began with oncogenes -- those genes associated with malignant cell transformation or abnormal cancer cell proliferation -- but has recently turned to anti-oncogenes.  The anti-oncogene protects cells from becoming cancerous, but when they have a mutation that causes a loss or reduction in function, they may allow the cell to progress to cancer.  These mutations may occur in multiple genes and, as such, make it difficult to pinpoint particular cancers’ genetic origins.

This invention seeks to elucidate the mechanism of malignant transformation of oral-cavity-derived cells at the gene level in order to diagnose the malignancy of OSCC, and suppress its proliferation. The invention also seeks to enable the development of targeted drug therapies by identifying and targeting genes exhibiting characteristic behavior in OSCC. To that end, the inventors selected hundreds of DNA types to subject to the well-known comparative genomic hybridization method to rapidly analyze genetic abnormalities accompanying amplification or deletion of numerous genes. Through this method, they discovered that deletion or inactivation of the MTNR1A gene, and specifically a decrease in the MTNR1A protein, significantly promotes proliferation of the OSCC. 

This claimed invention sounds remarkably similar to controversial patents held by Myriad Genetics -- and therein lies the problem. The US Supreme Court recently decided the Prometheus case, invalidating their patents for being based on laws of nature, and remanded the pending Myriad case back to the Federal Circuit to be decided in view of its opinion. While the Prometheus case involved administration of a drug for treatment of Crohn’s disease, the Court’s emphasis on the claimed method’s roots in laws of nature has the public wondering whether Myriad’s patents covering genes predicting susceptibility to breast and ovarian cancers will similarly be found unpatentable. 

Just as the scientists behind this oral carcinoma patent have done, Myriad’s researchers used well-known methods to narrow down the field of possible culprit genes to the two responsible for development of breast and ovarian cancers. The steps they used were public knowledge, the materials they started with were publicly available, and the genes they pinpointed were naturally existing genes. They isolated and purified these genes, but opponents of gene patenting practices have made convincing arguments that isolated genes are no different from their in vivo counterparts.  


Any steps taken towards discovering the underlying causes of cancer are, of course, positive. If doctors are able to identify heightened susceptibility in their patients for particular cancers, they will be able to act preemptively.  


If the Federal Circuit finds the Myriad patents invalid, the decision will call into question all gene-based patents. There are many who feel very strongly that genes are naturally occurring elements of living organisms that may be identified, but cannot be “discovered” or “invented” within the meaning of US patent law. If the Federal Circuit agrees, this patent may be invalidated.  

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