<prompt> Which of the following about tobacco and oral cancer are true? i. MC histological type - adenocarcinoma ii. Dose-response relationship iii. Synergistic interaction with alcohol iv. Associated with mutations in p53 gene. No association with smokeless tobaccoi, ii, iii, ivii, iii, ivii, iiii, iii, iv,  <response>: Risk Factors for CA Oral Cavity- Tobacco- Alcohol- Betelnut Areca nut- Pan Masala- Sharp Jagged tooth- Plummer Vinson syndrome- Ill-fitting denture- Syphilitic glossitis- HPV infections- EBV- Poor nutrition Impoant points of carcinoma of oral cavity:- MC mutation: In CA oral cavity - P53- MC site of CA Oral cavity - Tongue lip- MC histological type - SCC- MC type of cancer in India - CA oral cavity Buccal Mucosa Anterior Tongue LowerAlveolus- MC pattern of spread - local extension and regional lymphatic spread- MC site of LN metastasis - lungs- MC lymph node metastasis - CA Tongue- Least common lymph node metastasis - CA lip CA Hard Palate- BL lymphatic spread lower lip Supraglottis Soft Palate- IOC for Dx - Edge Biopsy Not from centre to avoid taking sample from necrotic areas- IOC for staging of Head and Neck Malignancies including CA Oral Cavity - MRI- MC flap used for Head Neck reconstruction - PMMC flap Pectoralis major myocutaneousflap - Based on Pectoral branch of Thoraco-Acromial vesselsSkin andvermillion 