Question

The topic is how cancer works?

Molecular characterization of breast cancer typically involves immunostain- ing to measure the levels of HER2 whereas molecular characterization of lung cancer is more likely to do sequencing to measure mutations in EGFR. Why is this?

Answer 1

In this case, remember that cancer is characterized by an uncontrolled proliferation. This is thanks to several mutated genes involved in cell proliferation. It is common to observe that genes that code for receptors of growing factors are overexpressed on the surface of tumor cells. These receptors bind to several growing factors and promotes the cell proliferation. In the case of breast cancer, we can find hormone receptors such as estrogen receptors. However, in more aggressive type of breast cancers, we can find the HER2 receptor. The same happens with the lung cancer and the Epidermal Growth Factor receptor. What you must understand is that tumor cells requires a lot of signals and nutrients in order to proliferate. For this reason, they overexpress these kind of receptors and that is why we use them as diagnostic prediction