<prompt> The most common pre-malignant condition of oral carcinoma is -LeukoplakiaErythroplakiaLichen planusFibrosis  <response>: Two important premalignant lesions for oral cancer are : -LeukoplakiaErythroplakiaLeukoplakia is the most common premalignant lesions.But, the risk of malignant transformation of erythroplakia is much higher than that seen with leukoplakia.The most common predisposing factor for both these conditions is smoking. 