title: Micropapillary pattern and poorly differentiated clusters represent the same biological phenomenon in colorectal cancer: a proposal for a change in terminology.
abstract: OBJECTIVE
  Colorectal carcinomas (CRCs) with a micropapillary pattern and those showing high counts of poorly differentiated clusters (PDCs) are characterized by a higher probability to develop nodal metastases and have a worse prognosis. In light of the morphologic similarity to the micropapillary component, we aimed to verify whether PDCs also display an inverted secretory pattern.
  
  
  METHODS
  The immunohistochemical expression of MUC1 and E-cadherin was assessed in a cohort of CRCs with PDCs and compared with that observed in CRCs without PDCs.
  
  
  RESULTS
  PDCs in our cases always displayed an inverted MUC1 pattern. In addition, we found abnormal (lost or cytoplasmic) expression of E-cadherin in PDCs.
  
  
  CONCLUSIONS
  The altered expression of MUC1 and E-cadherin may account for the aggressive behavior and higher metastatic potential of CRCs with high PDC counts and indicate an epithelial-mesenchymal transition. Our findings suggest that regardless of the morphologic aspect, PDCs and the micropapillary component may reflect the same biological phenomenon in CRCs. Thus, we wonder whether the micropapillary areas should be considered a variant of CRCs or more objectively counted as PDCs to predict prognosis. We also believe that the term PDC better describes the biological phenomena underlying this peculiar morphologic aspect in comparison with the misnomer micropapillary.
authors.affiliation: From the Department of Human Pathology "Gaetano Barresi," University of Messina, Messina, Italy. vbarresi@unime.it.
authors.forename: Valeria
authors.initials: V
authors.lastname: Barresi
authors.affiliation: From the Department of Human Pathology "Gaetano Barresi," University of Messina, Messina, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Branca
authors.affiliation: From the Department of Human Pathology "Gaetano Barresi," University of Messina, Messina, Italy.
authors.forename: Enrica
authors.initials: E
authors.lastname: Vitarelli
authors.affiliation: From the Department of Human Pathology "Gaetano Barresi," University of Messina, Messina, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tuccari
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018396:Mucin-1 / Q000378:metabolism*; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D018396:Mucin-1
keywords: Colorectal cancer; E-cadherin; MUC1; Micropapillary; Poorly differentiated clusters; Tumor budding