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 tobacco

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)- B/L 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