Mains Paper 2 : Health & Education |
From UPSC perspective, the following things are important :
Prelims level : Biomarkers
Mains level : Not Much
- By looking out for five biomarkers, it is now possible to tell in advance if a person with oral cancer of the gum and cheek has lymph node metastasis even before surgery is undertaken.
What are Biomarkers?
- In medicine, a biomarker is a measurable indicator of the severity or presence of some disease state.
- More generally a biomarker is anything that can be used as an indicator of a particular disease state or some other physiological state of an organism.
Biomarkers to check oral cancer
- The ability to correctly predict absence/presence of lymph node metastasis in oral cancer patients is 80-90% based on the five biomarkers.
- As a result, an oral cancer patient can be spared of a neck dissection to investigate if the cancer has spread to the lymph nodes in case the five biomarkers are absent.
- Lymph node dissection increases morbidity. However, if the patient tests positive for even one biomarker then an aggressive treatment would be required.
- An oral cancer patient with cancer spread to the lymph node has a 50% lower chance of survival for five years or more compared with patients in whom it has not spread to the lymph node.
Five genomic biomarkers
- The team found that lymph node metastasis was associated with five genomic biomarkers.
- There are five genomic features or biomarkers of lymph node metastasis in oral cancer patients.
- Two of these are rare, heritable DNA changes in BRCA2 and FAT1 genes.
- The remaining three are non-heritable (somatic) DNA alterations.
Diagnosing oral cancer metastasis
- In oral cancer patients, the cancer cells tend to commonly spread to the lymph node in the neck.
- But not all oral cancer patients have the tendency for the cancer to spread to other organs (metastasis).
- Oral cancer patients who have lymph node metastasis possess DNA alterations in specific genes that provide cancer cells the ability to spread.
- These DNA alterations are different from those that cause the primary cancer, and these alterations arise independent of the stage of cancer.
- So in some patients, the cancer would have spread to the lymph node even at an early stage of oral cancer, while in some patients with advanced (T4 stage) oral cancer, the cancer would not have spread.