Final answer:
Therapy involving ncRNAs can be used to treat cancer when ncRNAs act as oncogenes but not when they act as tumor suppressors.
Step-by-step explanation:
Therapy involving ncRNAs would be used to treat cancers in which ncRNAs act as oncogenes. In these types of cancers, the overexpression of certain ncRNAs could be detrimental to normal cellular activity, and targeting and reducing their expression could be an effective treatment.
On the other hand, therapy involving ncRNAs would not be used to treat cancers in which ncRNAs act as tumor suppressors. In these cancers, ncRNAs play a role in inhibiting tumor growth, and increasing their expression would actually be beneficial.