Loss of the CBX7 gene expression correlates with a highly malignant phenotype in thyroid cancer.
Using gene expression profiling, we found that the CBX7 gene was drastically down-regulated in six thyroid carcinoma cell lines versus control cells. The aims of this study were to determine whether CBX7 is related to the thyroid cancer phenotype and to try to identify new tools for the diagnosis and prognosis of thyroid cancer. We thus evaluated CBX7 expression in various snap-frozen and paraffin-embedded thyroid carcinoma tissues of different degrees of malignancy by quantitative reverse transcription-PCR and immunohistochemistry, respectively. CBX7 expression progressively decreased with malignancy grade and neoplasia stage. Indeed, it decreased in an increasing percentage of cases going from benign adenomas to papillary (PTC), follicular, and anaplastic (ATC) thyroid carcinomas. This finding coincides with results obtained in rat and mouse models of thyroid carcinogenesis. CBX7 loss of heterozygosity occurred in 36.8% of PTC and in 68.7% of ATC. Restoration of CBX7 expression in thyroid cancer cells reduced growth rate, with a retention in the G(1) phase of the cell cycle, suggesting that CBX7 can contribute to the proliferation of the transformed thyroid cells. In conclusion, loss of CBX7 expression correlates with a highly malignant phenotype in thyroid cancer patients.
Pallante
Pierlorenzo
P
Istituto di Endocrinologia ed Oncologia Sperimentale del CNR c/o Dipartimento di Biologia e Patologia Cellulare e Molecolare, Facoltà di Medicina e Chirurgia, Università degli Studi di Napoli Federico II, Naples, Italy .
Federico
Antonella
A
Berlingieri
Maria Teresa
MT
Bianco
Mimma
M
Ferraro
Angelo
A
Forzati
Floriana
F
Iaccarino
Antonino
A
Russo
Maria
M
Pierantoni
Giovanna Maria
GM
Leone
Vincenza
V
Sacchetti
Silvana
S
Troncone
Giancarlo
G
Santoro
Massimo
M
Fusco
Alfredo
A
D018263:Adenocarcinoma, Follicular / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002291:Carcinoma, Papillary / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics; D003114:Colony-Forming Units Assay; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D019656:Loss of Heterozygosity; D051379:Mice; D008819:Mice, Nude; D063150:Polycomb Repressive Complex 1; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013961:Thyroid Gland / Q000378:metabolism / Q000473:pathology; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
C503627:CBX7 protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1