Expression and significance of TTF-1,CK7,CK5/6,P63 and CK20 in mucin producing lung cancer

Objective To evaluate the expression patterns of TTF-1,CK7,CK5/6,P63 and CK20 in mucin producing lung cancer,and investigate the utility of immunohistochemical markers in differential diagnosis.Methods 15 mucin producing carcinoma of lung,including 5 signet ring cell adenocarcinoma,4 intestinal type adenocarcinoma. 3 mucinous bronchioloalveolar carcinoma,2 solid adenocarcinoma with mucin production,and 1 mucinous (colloid) adenocarcinoma,50 conventional lung adenocarcinoma(13 non-mucinous bronchioloalveolar carcinoma) were Studied with a panel of immunoslains.Results TTF-1 were expressed in 60.0%(9/15) of mucin producing carcinoma of lung and 94.0%(47/50) in lung adenocarcinoma;Mucin producing carcinoma of lung and lung adenocarcinoma exhibit a high frequency of CK7 expression with 100%(15/15) and 96.0%(48/50) respectively;CK5/ 6 expression was 0 and 2.0%(1/50) respectively;P63 was 13.3%(2/15) and 12.0%(6/50);CK20 expression was 6.7%(1/15) and 0,while negative immunohistochemical reactivity was seen in all lung adenocarcinoma.Conclusion Compared with lung adenocarcinoma,mucin producing carcinoma of lung often exhibit lower frequency of TTF- 1 and CK20 positive expression;CK7 positive expression was useful for confirming origin of lung cancer.