In the microarray analysis some genes, such as ERB-B2 and ESR1, have been found to be associated with particular disease or conditions such as cancer. Other genes, such as the ABC-B2 gene, are not associated with a disease but are involved in resistance to certain drugs or treatments. Why would it be useful to test for the expression of genes like the ABC-B2 gene on the microarray

The expression of genes associated with drug resistance leads to the reduction in the effectiveness of drugs against cancer cells.

Explanation:

In cancer, drug resistance is produced when oncogenic cells are able to develop mechanisms of resistance against drugs such as, for example, chemotherapeutic agents. In these cases, therapeutic treatments become ineffective to fight against cancer cells and tumor progression. In consequence, it is imperative to trace the expression of target oncogenes associated with drug resistance in order to provide effective treatments to eliminate cancer cells.

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