title: Pulmonary adenocarcinoma with a micropapillary pattern: a clinicopathological, immunophenotypic and molecular analysis.
abstract: OBJECTIVE
  To investigate the clinicopathological and molecular characteristics, immunohistochemical profile and prognosis of pulmonary adenocarcinoma with a micropapillary pattern (MPPAC).
  
  
  RESULTS
  Eight hundred and eighty-six pulmonary adenocarcinomas were divided into two groups: micropapillary pattern (MPP)-positive (≥1% MPP) (n = 246) and MPP-negative (n = 640), and clinicopathological characteristics were analysed. Of these, 66 cases with extensive MPP (MPP ≥ 50%) were studied by immunohistochemistry for several markers, and mutational analysis of K-ras and epidermal growth factor receptor (EGFR) with the Scorpion Amplification Refractory Mutation System. Smoking, TNM stage, lymph node metastasis, lymphatic invasion, venous invasion, pleural invasion and differentiation grade were significantly associated with the prognosis of MPPAC (P < 0.05). Immunohistochemically, the positive rate in the MPP-positive group was 100% for E-cadherin, 100% for β-catenin, 93.9% for Muc-1, 57.6% for EGFR, 37.9% for p53, and 95.5% for Ki67. No differences were identified between MPP and non-MPP tissue within the same tumour with regard to K-ras and EGFR mutations. The 5-year survival rates of patients were significantly different between the MPP-positive group and the MPP-negative group (P = 0.005). By multivariate analysis, a MPP was an independent prognostic factor for lung adenocarcinomas.
  
  
  CONCLUSIONS
  MPP represents a distinct histopathological variant with biological and prognostic significance.
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Liang
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Luo
authors.forename: Tonghua
authors.initials: T
authors.lastname: Liu
mesh_terms: D000231:Adenocarcinoma, Papillary / Q000235:genetics / Q000401:mortality* / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D004252:DNA Mutational Analysis; D005260:Female; D018773:Genes, erbB-1; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000235:genetics / Q000401:mortality* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins