Is it permissible for my wife to undergo a breast implant procedure using a part of the skin from her buttocks after her breast was removed due to cancer?

There is no objection to breast augmentation surgery, as it falls under the category of removing a defect and restoring something to its original creation by Allah. This is supported by the hadith of Arfajah ibn As'ad, whose nose was cut off, so he fashioned a nose of gold by the command of the Prophet, peace and blessings be upon him. Similarly, the Permanent Committee for Scholarly Research and Ifta' has permitted cosmetic surgeries to remove clear defects that cause embarrassment, such as prominent breasts or a large nose, provided there is a strong presumption of the surgery's success and that it will not result in harm greater than or equal to its benefit. There is also no objection to taking a portion of skin from the buttocks to complete the procedure.