<prompt> Most common site for squamous cell ca. esophagus isUpper thirdMiddle thirdLower thirdGastro-esophageal junction  <response>: Ans. is b i.e., Middle third Distribution of Squamous cell Ca Upper 13 10 Middle 13 60 Lower 13 30 Values according to Sabiston 17e, may be different in other texts but are approx. the same 