Ultrasound elastography has been a very useful tool in predicting the risk of malignant thyroid
tumor for several years. The objective of this study was to determine if there is a correlation between strain ratio (SR),
collagen deposition and
transforming growth factor β1 (TGF-β1) expression in different types of
thyroid nodules and if TGF-β1 is related to cervical
lymph node metastasis. 102 nodules from 81 patients who underwent thyroid resection surgery in our hospital were retrospectively studied. All of these patients had undergone ultrasound elastography scanning before surgery. Masson staining and immunohistochemical staining were used to evaluate the ratio of expression of
collagen deposition and TGF-β1. There was a significant difference between benign and malignant
thyroid nodules in SR (8.913 ± 11.021 vs. 1.732 ± 0.727, p = 0.000),
collagen content (0.371 ± 0.125 vs. 0.208 ± 0.057, p = 0.000) and TGF-β1 expression (0.336 ± 0.093 vs. 0.178 ± 0.071, p = 0.000). A cutoff of 2.99 for SR measurement was selected for the highest Youden index for predicting malignant
thyroid nodules, which yielded 87.88% sensitivity, 100% specificity, 100% positive predictive value, 83.72% negative predictive value and 92.15% accuracy. Expression of
collagen and TGF-β1 was positively correlated with SR measurements (coefficient = 0.839 for
collagen and 0.855 for TGF-β1, p = 0.000). Among 61 nodules with
papillary thyroid carcinoma, the average SR for the
metastasis group was higher than that for the non-
metastasis group (10.955 ± 13.805 and 7.852 ± 7.931, respectively), but without statistical significance (p = 0.287).
Collagen deposition was significantly higher in the
metastasis group than in the non-
metastasis group (0.421 ± 0.091 vs. 0.353 ± 0.118, p = 0.011). TGF-β1 expression was also significantly higher in the
metastasis group than in the non-
metastasis group (0.378 ± 0.0.69 vs. 0.328 ± 0.091, p = 0.016). To conclude, TGF-β1 may contribute to
thyroid nodule elasticity by promoting
collagen deposition. In
papillary thyroid carcinoma, overexpression of TGF-β1, as well as
collagen deposition, may be a risk factor for cervical
lymph node metastasis.