OVEREXPRESSION OF MUC5 GENES IS ASSOCIATED WITH EARLY POSTOPERATIVE METASTASIS IN NON-SMALL-CELL LUNG-CANCER

Mucin glycoprotein can promote tumor-cell invasion metastasis and modu late the immune recognition of cancer. This study aimed to elucidate t he clinical significance of mucin gene overexpression in lung cancer. We collected 60 lung cancer sampler and paired non-tumorous lung porti ons of varying types and stages. Slot-blot analysis with specific anti -sense oligonucleotide probes derived from tandem repeat sequence of M UC1, -2, -3, -4, 5B and 5AC were utilized to compare the amount of muc in gene mRNA in tumor samples with that of the nontumorous counterpart s. A ratio higher than 1.5 for each specific mucin mRNA amount was con sidered to indicate mucin gene overexpression in tumors. Immunohistoch emical staining of monoclonal antibodies against mature airway mucin ( 17Q2) and MUC1 mucin protein (HMFG2) were also used to analyze mucin p rotein. The study showed that overexpression of mucin genes frequently occurred in lung cancer (25 out of 60, 41.7%), but that there was no preferential expression of a particular mucin gene or a combination of mucin genes in these tumors. The overexpression of mucin genes and mu cin protein had no correlation with tumor stage, nodal stage, histolog y or pathological differentiation grade. Tumors of smokers had higher- MUC5B and MUC5AC mRNA expression ratios than those of nonsmokers. Tumo rs with increased expression of mucin genes tended to be associated wi th post-operative relapse, especially when MUC5B and MUC5AC genes were overexpressed (p = 0.015 and 0.025, respectively). The study suggests that overexpression of novel tracheobronchial mucin genes may result in an increased likelihood of post-operative lung-cancer recurrence or metastases. (C) 1996 Wiley-Liss, Inc.