title: Expression of hypoxia-associated proteins in sporadic medullary thyroid cancer is associated with desmoplastic stroma reaction and lymph node metastasis and may indicate somatic mutations in the VHL gene.
abstract: Medullary thyroid carcinomas (MTCs) are mostly aggressive but slowly growing malignant tumours that metastasize early to loco-regional lymph nodes. Desmoplastic stroma reaction is a strong risk factor associated with lymph node metastases. We evaluated immunohistochemically the expression of two hypoxia-associated proteins, carbonic anhydrase IX (CAIX) and hypoxia-induced factor 1α (HIF1α), and ki-67, intercellular matrix adhesion molecule E-cadherin and the stroma remodelling marker tenascin C in a series of 100 sporadic MTCs and corresponding lymph node metastases, if present. Moderate to strong expression of CAIX was seen in 53 cases, and of HIF1α in 51 cases, showing a strong correlation (p < 0.001; Spearman's coefficient of correlation, 0.59). Expression correlated with the degree of desmoplasia (pCAIX = 0.001 and pHIF1α = 0.001), with tenascin C expression (pCAIX = 0.001,pHIF1α = 0.038), with the ki-67 proliferation index (pCAIX = 0.001, pHIF1α = 0.001) and with the presence of lymph node metastases (pCAIX < 0.001 and pHIF1α = 0.007). The absence of membranous E-cadherin staining was significantly associated with the grade of desmoplasia, tenascin expression and lymph node metastases(p ≤ 0.05) but not with ki67 proliferation index or expression of hypoxia-associated factors. Expression of hypoxia-associated proteins was in most cases identical between primary tumours and lymph node metastases.Two cases showed strong uniform expression of CAIX and HIF1α in the primary tumour as well as in the lymph node metastases, and sequencing revealed mutations in the coding regions of the Von-Hippel–Lindau gene (VHL ).Our findings suggest that despite of the fact that MTCs have only slowly growth, tumour hypoxia plays an important role in the development of loco-regional metastases. Since traditional cytotoxic chemotherapy has only little effect on MTCs, targeting hypoxia-associated and -regulated proteins might be of benefit for patients.
authors.affiliation: Clinical Institute of Pathology, Medical University of Vienna, Austria. oskar.koperek@meduniwien.ac.at
authors.forename: Oskar
authors.initials: O
authors.lastname: Koperek
authors.forename: Oliver
authors.initials: O
authors.lastname: Bergner
authors.forename: Bettina
authors.initials: B
authors.lastname: Pichlhöfer
authors.forename: Felicitas
authors.initials: F
authors.lastname: Oberndorfer
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Hainfellner
authors.forename: Klaus
authors.initials: K
authors.lastname: Kaserer
authors.forename: Reinhard
authors.initials: R
authors.lastname: Horvat
authors.forename: Adrian L
authors.initials: AL
authors.lastname: Harris
authors.forename: Bruno
authors.initials: B
authors.lastname: Niederle
authors.forename: Peter
authors.initials: P
authors.lastname: Birner
mesh_terms: D000368:Aged; D030741:Carbonic Anhydrase IV / Q000378:metabolism*; D018278:Carcinoma, Neuroendocrine; D004252:DNA Mutational Analysis / Q000379:methods; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D005355:Fibrosis; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000378:metabolism; D017154:Stromal Cells / Q000473:pathology; D019063:Tenascin / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics*
chemical_list: D004273:DNA, Neoplasm; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009363:Neoplasm Proteins; D019063:Tenascin; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D030741:Carbonic Anhydrase IV; C497446:VHL protein, human