Mucin‐producing adenocarcinoma of the lung, with special reference to goblet cell type adenocarcinoma: Immunohistochemical observation and Ki‐ ras gene mutation

To clarify its biological nature, 10 samples of goblet cell‐type adenocarcinoma of the lung were collected and compared with 10 other pulmonary much‐producing adene carcinomas with respect to Immunohistochemical features and the presence of Ki‐ ras gene mutation in codons 12 and 13. Goblet cell‐type adenocarcinomas lacked lmmunoreactlvlty for surfactant apoprotein and S‐100 protein‐positive Langerhans cells, which was in marked contrast to other mucin‐producing adenocarcinomas. In addition, the mucin gene products, MUC‐1 and MUC‐2 glycoproteins were immunohistochemically stained. The msuh showed that MUC‐1 giycoprotein is frequently expressed by mucin‐producing adenocarcinomas except the goblet cell‐type. Ki‐ ras gene mutation was detected in 12 of 20 (60%) mucin‐producing adenocarcinomas. These mutations were exclusively found in codon 12 and G to A transitions were the most frequent type of alteration in the KI‐ ras gene. In goblet cell‐type adenocarcinomas, the frequency of KI‐ ras gene mutation was 80% consisting of G to A transitions and G to T transversions in six and two tumors, respectively. Therefore, goblet cell‐type adenocarcinomas differed from other mucin‐producing adeno‐carcinomas in terms of immunohistochemical and molecular biological features, suggesting that goblet cell‐type adenocarclnomas are distinctly different from other subtypes of adenocarcinomas.