title: Mucinous micropapillary pattern in lung adenocarcinomas: a unique histology with genetic correlates.
abstract: OBJECTIVE
  In lung adenocarcinoma (ADC), micropapillary carcinomas (MPCs) are associated with poor prognosis because these tumours exhibit higher metastatic potential. Despite this, there are no studies investigating the differences between mucinous and non-mucinous MPC.
  
  
  RESULTS
  We evaluated the proportion of micropapillary components in lung ADCs, and compared the differences with respect to the presence or absence of associated mucin. Tumour specimens from 694 patients with consecutively resected primary lung ADC were reviewed, and 37 cases of invasive mucinous ADCs were excluded. A significant (≥5%) micropapillary component was noted in 320 (48.7%) of 657 evaluable cases. When the cases with micropapillary component were divided into 67 (20.9%) mucinous and 253 (79.1%) non-mucinous subtypes, tumours with mucinous micropapillary component exhibited significantly more aggressive pathological features, a higher proportion of HER2 mutations (P = 0.002) and ALK rearrangements (P < 0.001), and a lower proportion of EGFR mutations (P = 0.038) compared to those with a non-mucinous micropapillary component. In survival analyses, mucinous MPC tended to be more aggressive compared with non-mucinous MPC, but its prognostic value was not statistically significant (P = 0.076).
  
  
  CONCLUSIONS
  Mucinous micropapillary pattern is an under-recognized unique growth associated significantly with HER2 mutation and ALK rearrangement.
authors.affiliation: Division of Pathology and Clinical Laboratories, National Cancer Centre Hospital, Tokyo, Japan.|Division of Thoracic Surgery, National Cancer Centre Hospital, Tokyo, Japan.|Advanced Clinical Research of Cancer, Juntendo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Tsugumasa
authors.initials: T
authors.lastname: Kamata
authors.affiliation: Division of Pathology and Clinical Laboratories, National Cancer Centre Hospital, Tokyo, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshida
authors.affiliation: Division of Genome Biology, National Cancer Centre Research Institute, Tokyo, Japan.
authors.forename: Kouya
authors.initials: K
authors.lastname: Shiraishi
authors.affiliation: Division of Clinical Laboratories, National Cancer Centre Hospital, Tokyo, Japan.
authors.forename: Koh
authors.initials: K
authors.lastname: Furuta
authors.affiliation: Advanced Clinical Research of Cancer, Juntendo University Graduate School of Medicine, Tokyo, Japan.|Division of Hepatobiliary and Pancreatic Surgery, National Cancer Centre Hospital, Tokyo, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Kosuge
authors.affiliation: Division of Thoracic Surgery, National Cancer Centre Hospital, Tokyo, Japan.
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Department of Surgery, Division of General Thoracic Surgery, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Asamura
authors.affiliation: Division of Pathology and Clinical Laboratories, National Cancer Centre Hospital, Tokyo, Japan.|Department of Pathology and Laboratory Medicine, Kansai Medical University, Osaka, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Tsuta
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D002288:Adenocarcinoma, Mucinous / Q000235:genetics* / Q000473:pathology; D000231:Adenocarcinoma, Papillary / Q000235:genetics* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: human epidermal growth factor receptor 2 mutation; lung adenocarcinoma; micropapillary; mucinous