title: Up-regulation of the hypoxia-inducible factor-1 transcriptional pathway in colorectal carcinomas.
abstract: The aim of the study was to identify the impact on prognosis of hypoxia-inducible factor-1 genetic program in colorectal carcinomas and to develop an experimental procedure that would allow a reliable quantitative gene expression analysis in formalin-fixed and paraffin-embedded tissue. The expression of hypoxia-inducible factor-1alpha and 13 hypoxia-inducible factor-1 target genes (AMF, CAIX, VEGF, VEGFR1, VEGFR2, HGF, MET, TGFalpha, EGFR, IGF2, MMP2, PLAUR, NIX) was quantified by real-time polymerase chain reaction in 18 colorectal, poorly differentiated neuroendocrine carcinomas and in 60 invasive colorectal carcinomas. Moreover, hypoxia-inducible factor-1alpha protein expression was evaluated by immunohistochemistry. High levels of hypoxia-inducible factor-1alpha were positively associated with poorly differentiated neuroendocrine carcinoma histology (P < .005), poor differentiation (P < .025), presence of necrosis, and presence of microsatellite instability (P < .05). AMF, TGFalpha, IGF2, NIX, VEGF, and VEGFR2 transcripts were significantly higher in the very aggressive poorly differentiated neuroendocrine carcinomas than in exocrine colorectal carcinomas and TGFalpha expression was significantly associated with presence of lymph nodal metastases (P < .05). High levels of TGFalpha and NIX were significantly associated with decreased overall survival (P < .001; P < .01). The multivariate analysis showed that advanced stage, presence of lymph node metastases, and high TGFalpha expression had an independent effect on survival (P < .006; P < .01; P < .0006). Our study suggests an up-regulation of the hypoxia-inducible factor-1 transcriptional pathway in colorectal carcinomas. hypoxia-inducible factor-1alpha overexpression alone, has no impact on the prognosis of colorectal carcinomas likely because the consequences of hypoxia-inducible factor-1alpha expression/stabilization strongly depend on the genetic background of the transformed cells. Mechanisms leading to increased synthesis of hypoxia-inducible factor-1alpha mRNA via autocrine growth factor loops may play a crucial role in invasive growth in this site.
authors.affiliation: Department of Human Morphology, Anatomic Pathology Unit, University of Insubria, Varese, Italy. daniela.furlan@uninsubria.it
authors.forename: Daniela
authors.initials: D
authors.lastname: Furlan
authors.forename: Nora
authors.initials: N
authors.lastname: Sahnane
authors.forename: Ileana
authors.initials: I
authors.lastname: Carnevali
authors.forename: Roberta
authors.initials: R
authors.lastname: Cerutti
authors.forename: Francesco
authors.initials: F
authors.lastname: Bertoni
authors.forename: Ivo
authors.initials: I
authors.lastname: Kwee
authors.forename: Silvia
authors.initials: S
authors.lastname: Uccella
authors.forename: Valentina
authors.initials: V
authors.lastname: Bertolini
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Chiaravalli
authors.forename: Carlo
authors.initials: C
authors.lastname: Capella
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000401:mortality / Q000556:secondary; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D018278:Carcinoma, Neuroendocrine / Q000235:genetics* / Q000401:mortality / Q000556:secondary; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics* / Q000378:metabolism; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D009336:Necrosis; D011379:Prognosis; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D012334:RNA, Neoplasm