The molecular method used to determine the presence or absence of a biomarker depends on the type of mutation. As mentioned previously, oncogenes are only activated by specific point mutations in the gene. These mutations are easily detected by polymerase chain reaction (PCR). Tumor suppressors can be deactivated by any number of mutations, therefore only testing a few sites in the tumor suppressor gene would be insufficient. Tumor suppressor gene analysis is usually performed by sequencing so that every base in the gene sequence can be interrogated.
The method used to determine the presence or absence of a biomarker needs to be sensitive enough to detect the mutation in a low number of cancer cells. The method chosen should also be cost and time efficient. If multiple biomarkers need to be evaluated it is often faster and cheaper to perform massively parallel sequencing or next generation sequencing (NGS) than it would be to perform PCR or Sanger sequencing.
