Among the 897 non-mucinous adenocarcinomas, 61 PMPA with ≤90% mucin and 39 PMPA with >90% mucin, ALK rearrangements were found in 47 (5.2%) non-mucinous adenocarcinomas, 9 (14.8%) PMPA with ≤90% mucin and 12 (30.8%) PMPA with >90% mucin, respectively, with an ordinal association (coefficient, 95% CI=0.11, 0.06 to 0.17).
Pulmonary invasive mucinous adenocarcinomas and mixed nonmucinous/mucinous adenocarcinomas are clinically and genetically similar, except for a higher rate of ALK rearrangement in mixed tumors.
In conclusion, aberrant ALK expression is observed in ovarian serous carcinoma but not in mucinous carcinoma, is independent of gene translocation, and might be associated with progression and prognosis.
Of the 18 ALK fusion-positive lung adenocarcinomas, 8 cases (44.4%) were histologically diagnosed as subtypes of cribriform adenocarcinoma, 7 cases (38.9%) as cribriform adenocarcinoma mixed with papillary and/or mucinous pattern, 2 cases (11.1%) as papillary adenocarcinoma, and 1 case (5.6%) as mucinous adenocarcinoma.