RAD52 motif containing 1 (RDM1) encodes the RAD52 protein involved in DNA double-strand break repair and recombination events. However, the importance of RDM1 in papillary thyroid carcinoma (PTC) is largely unknown. In the present study, we examined the role of RDM1 in thyroid cancer. The RDM1 expression in PTC patients was examined using immunohistochemistry. The expression levels of RDM1 mRNA in thyroid cancer cells were measured by quantitative real-time PCR (qRT-PCR). Lentivirus-mediated small interfering RNAs (siRNAs) were used to knock down the RDM1 expression in the K1 and TPC1 cells. Then, changes in the RDM1 target gene expression were determined by qRT-PCR and Western blot. Cell proliferation was examined by a high content screening assay. Cell cycle distribution and apoptosis were detected by flow cytometric analysis and MTT analysis. We showed that the RDM1 expression was higher in PTC tissue compared to pericarcinous tissue. RDM1 mRNA was found to be expressed by qRT-PCR. Using a lentivirus-based RNA interference (RNAi) approach, the RDM1 expression was significantly inhibited. The inhibition of RDM1 expression by RNAi significantly impaired cell proliferation, increased apoptosis and arrested cells in the G2/M phase. These data showed that RDM1 was highly expressed in PTC tissue and thyroid cancer cell lines. Moreover, RDM1 may play an important role in cell proliferation, cell cycle distribution and apoptosis of human PTC cells.
Wei Li, Qing Huang, Danyang Sun, Guizhi Zhang and Jian Tan
Wei Sun, Boyuan Zheng, Zhihong Wang, Wenwu Dong, Yuan Qin and Hao Zhang
In patients with papillary thyroid cancer (PTC) with clinical negative central lymph nodes (cN0), the use of prophylactic central lymph node dissection remains controversial. Contralateral central lymph node metastasis (CCLNM) occurs in 3.88–30.63% of patients with cN0 PTC. Therefore, the present meta-analysis aimed to obtain evidence for CCLNM risk factors in unilateral cN0 PTC.
Materials and methods
Relevant studies were identified in the PubMed, SCIE, and Wanfang databases up to Oct 31, 2019. The included patients had undergone lobectomy or total thyroidectomy with bilateral central lymph node dissection and were diagnosed pathologically with PTC. Revman 5.3 software was applied for statistical analysis.
Thirteen studies comprising 2449 patients were included. The factors associated with increased CCLNM risk in patients with cN0 disease were: age <45 years (odds ratio (OR) = 1.89, 95% CI = 1.43–2.49, P < 0.00001), male sex (OR = 1.67, 95% CI = 1.24–2.24, P = 0.0007), extrathyroidal extension (OR = 1.63; 95% CI = 1.17–2.28; P = 0.004), tumor size ≥1 cm (OR = 2.63, 95% CI 1.85–3.74, P < 0.00001), lymphovascular invasion (OR = 4.27, 95% CI = 2.47–7.37, P < 0.00001), and ipsilateral central lymph node metastasis (OR = 11.42, 95% CI = 5.25–24.86, P < 0.00001). However, no association was found for capsular invasion, multifocality, or Hashimoto thyroiditis.
The meta-analysis identified that age <45 years, tumor ≥1 cm, male sex, lymphovascular invasion, extrathyroidal extension, and ipsilateral central lymph node metastasis are related to CCLNM in patients with unilateral CN0 PTC. These factors should influence the use of prophylactic central lymph node dissection in this group of patients.