Investigators say that they have narrowed down 50 genes that
play a role in identifying the four subtypes of breast cancer.
By measuring the expression level of these genes in the tumors,
they were also able to determine how each individual will
respond to chemotherapy. Besides these four tumor types—luminal
A, luminal B, HER2-enriched, and basal-like—a fifth breast
cancer type known as normal-like has also been identified.
According to the current research, the team says that the
normal-like classification is really an indicator that a sample
contains insufficient tumor cells to make a molecular diagnosis
and that a new sample needs to be taken. The scientists analyzed
the gene activity of more than 1,000 breast tumors to identify
and validate the genetic signature of each of the four types of
breast cancer. Although the cancer types are distinguished by
thousands of genetic differences, the researchers were able to
pinpoint 50 genes that could identify each type. The researchers
also compared the activity o