Increased gene expression of TIMP1 and CHI3L1 in fine-needle aspiration biopsy samples from papillary thyroid cancer as compared to benign nodules.

BACKGROUND

Thyroid nodules are common ultrasound findings with malignancy rate 7%-15%. Our objective was to assess the relative expression of the tissue inhibitor of metalloproteinase-1 gene (TIMP1) and chitinase-3-like protein 1 gene (CHI3L1) in fine-needle aspiration biopsy (FNAB) washouts and the serum levels of their protein products (TIMP-1 and chitinase-3-like protein 1 known as YKL-40) in patients with papillary thyroid cancer (PTC) and patients with benign nodules. Furthermore, the correlation between gene expression and circulating protein product was evaluated.

METHODS

Eighty patients who underwent FNAB in one tertiary center were recruited in the study. Forty with Bethesda V and VI nodules were operated and PTC was confirmed. The other 40 patients were with Bethesda II nodules. TIMP-1 and YKL-40 serum levels were measured in all subjects. The TIMP1 and CHI3L1 expression was assessed in FNAB washouts from 20 PTC patients and 20 benign cases using quantitative PCR.

RESULTS

The relative expression of TIMP1 and CHI3L1 was significantly higher in the PTC group than in the benign group (p < .001 for TIMP1; p = .018 for CHI3L1). The PTC patients had higher serum TIMP-1 than the patients with benign nodules (p = .036). We did not find significant difference in the YKL-40 level between the two groups. TIMP1 and CHI3L1 expression did not correlate with the serum levels of their protein products.

CONCLUSION

FNAB washouts could be used for identification of diagnostic markers. The increased TIMP1 and CHI3L1 expression implies a role of these genes in the PTC carcinogenesis.