Virologists are modifying lentiviruses as vectors for carrying proto-oncogenes into cancer-transformed cells in culture. They are developing this virus for inserting the ras proto-oncogene directly into its correct location in the genome. The correct ras gene will already be linked to human DNA on either side of it and complexed with a recombination enzyme that will insert it into its correct location within the human genome. At the same time, the recombination enzyme will excise the defective oncogenic form of ras. The cells in culture should again come under normal hormonal control and require extra-cellular signals in order to continue dividing. Would this discovery be more useful for: a. reducing cancer risks
b. correcting/restoring cancer cells to normal
c. destroying cancerous tissue.