title: Expression of prolactin receptor and prolactin in normal and malignant thyroid: a tissue microarray study.
abstract: OBJECTIVE
  There is increasing evidence involving prolactin (PRL) and its receptor (PRLR) in the development of different cancers. The aim of the present study was to investigate the expression of PRLR and PRL in human thyroid tissues.
  
  
  METHODS
  Using tissue microarray (TMA) by immunohistochemical staining, we examined the expression level of PRLR and PRL in 314 specimens from 71 thyroid cancer patients and 15 normal thyroid samples.
  
  
  RESULTS
  Expression of the PRLR was observed in 93.3% of normal thyroid samples and in 76.1% of all thyroid cancers, while expression of PRL was observed in only 10% of medullary thyroid carcinomas and not at all in the other specimens, whether normal or neoplastic. Moreover, results suggested an overexpression of PRLR in 70% of medullary thyroid carcinomas, whereas 53.3% of poorly differentiated thyroid carcinomas showed a negative pattern of staining (p = 0.014 vs normal).
  
  
  CONCLUSIONS
  Present data revealed, for the first time, a widespread expression of PRLR in normal and neoplastic human thyroid tissues as well as a scarce expression of PRL, observed only in a few medullary thyroid carcinomas. Whether the overexpression of PRLR observed in medullary thyroid carcinomas or the underexpression of PRLR observed in poorly differentiated thyroid carcinomas play a contributory role in the oncogenesis of these tumors remains to be determined.
authors.affiliation: Centro de Investigação de Patobiologia Molecular, de Lisboa Francisco Gentil E.P.E., Lisboa, Portugal.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Costa
authors.forename: Ana Luísa
authors.initials: AL
authors.lastname: Catarino
authors.forename: Fernanda
authors.initials: F
authors.lastname: Silva
authors.forename: Luís G
authors.initials: LG
authors.lastname: Sobrinho
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Bugalho
mesh_terms: D018276:Carcinoma, Medullary / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D011388:Prolactin / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011981:Receptors, Prolactin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013961:Thyroid Gland / Q000033:anatomy & histology / Q000378:metabolism* / Q000473:pathology; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology; D046888:Tissue Array Analysis
chemical_list: D012333:RNA, Messenger; D011981:Receptors, Prolactin; D011388:Prolactin