ECM1 and TMPRSS4 are diagnostic markers of malignant thyroid neoplasms and improve the accuracy of fine needle aspiration biopsy.
OBJECTIVE
The objective of this study was to determine whether genes that regulate cellular invasion and metastasis are differentially expressed and could serve as diagnostic markers of malignant thyroid nodules.


BACKGROUND
Patients whose thyroid nodules have indeterminate or suspicious cytologic features on fine needle aspiration (FNA) biopsy require thyroidectomy because of a 20% to 30% risk of thyroid cancer. Cell invasion and metastasis is a hallmark of malignant phenotype; therefore, genes that regulate these processes might be differentially expressed and could serve as diagnostic markers of malignancy.


METHODS
Differentially expressed genes (2-fold higher or lower) in malignant versus benign thyroid neoplasms were identified by extracellular matrix and adhesion molecule cDNA array analysis and confirmed by real-time quantitative polymerase chain reaction (PCR). The area under the receiver operating characteristic (AUC) curve was calculated to determine diagnostic accuracy of gene expression level cutoffs established by logistic regression analysis.


RESULTS
By cDNA array analysis, ADAMTS8, ECM1, MMP8, PLAU, SELP, and TMPRSS4 were upregulated, and by quantitative PCR, ECM1, SELP, and TMPRSS4 mRNA expression was higher in malignant (n = 57) than in benign (n = 38) thyroid neoplasms (P< 0.002). ECM1 and TMPRSS4 mRNA expression levels were independent predictors of a malignant thyroid neoplasm (P < 0.003). The AUC was 0.956 for ECM1 and 0.926 for TMPRSS4. Combining both markers improved their diagnostic use (AUC 0.985; sensitivity, 91.7%; specificity, 89.8%; positive predictive value, 85.7%; negative predictive value, 82.8%). ECM1 and TMPRSS4 expression analysis improved the diagnostic accuracy of FNA biopsy in 35 of 38 indeterminate or suspicious results. The level of ECM1 mRNA expression was higher in TNM stage I differentiated thyroid cancers than in stage II and III tumors (P < or = 0.031).


CONCLUSIONS
ECM1 and TMPRSS4 are excellent diagnostic markers of malignant thyroid nodules and may be used to improve the diagnostic accuracy of FNA biopsy. ECM1 is also a marker of the extent of disease in differentiated thyroid cancers.
Kebebew
Electron
E
Endocrine Surgery and Oncology Program, Comprehensive Cancer Center, University of California, San Francisco, CA 94143, USA. kebebewe@surgery.ucsf.edu
Peng
Miao
M
Reiff
Emily
E
Duh
Quan-Yang
QY
Clark
Orlo H
OH
McMillan
Alex
A
D014408:Biomarkers, Tumor / Q000235:genetics*; D044963:Biopsy, Fine-Needle; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D015870:Gene Expression; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D020411:Oligonucleotide Array Sequence Analysis; D012697:Serine Endopeptidases / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology
D014408:Biomarkers, Tumor; D016326:Extracellular Matrix Proteins; D008565:Membrane Proteins; D012697:Serine Endopeptidases; C490607:ECM1 protein, human; C421305:TMPRSS2 protein, human