To()() cases arising from () of their respective laws, the rules and regulations promulgated thereunder and their Codes of Ethics and, for this purpose, may issue summons, subpoena and subpoena duces tecum to alleged violators and/or witnesses to compel their attendance in such investigations or hearings: Provided, That, the decision of the Professional Regulatory Board shall, unless appealed to the Commission, become final and executory after fifteen (15) days from receipt of notice of judgment or decision