[Predictive analysis of distant metastasis after primary treatment of papillary thyroid cancer in patients under 18 years old]

Objective: To investigate the distant metastasis after primary treatment of papillary thyroid cancer (PTC) in children and adolescents. Methods: A retrospective analysis of 180 cases (54 boys and 126 girls, with an age range of 6-18 years) with PTC treated at the Chinese Medical Academy Cancer Hospital and Zhejiang Cancer Hospital from January 1, 2001 to December 31, 2014 was performed. Patients' clinical and pathological data were collected. The follow-up results were statistically analyzed. The distant metastasis rate during the follow-up period was analyzed by the Kaplan-Meier method. Log-Rank test was used for univariate analysis and Cox regression model was established in multivariate analysis. Results: Twenty-four cases (13.3%) had distant metastases during following-up with a median of 92 months. The Log-Rank test showed that the younger age ≤15 years old (χ(2)=11.803, P=0.001), the larger tumor diameter >20 mm (χ(2)=5.776, P=0.016), multifocal (χ(2)=11.205, P=0.001), bilateral tumor distribution (χ(2)=19.804, P=0.001), invaded capsule (χ(2)=10.808, P=0.001), and bilateral lymph nodes metastasis (χ(2)=6.278, P=0.012) were risk factors for distant metastasis after initial treatment. The Cox regression analysis showed that age ≤15 years (hazard ratio [95% confidence interval]: 4.08[1.504-11.111], P=0.006) and bilateral tumor distribution (hazard ratio [95% confidence interval]: 4.77[1.903-11.966], P=0.001) were independent risk factors for distant metastasis after initial treatment. The risk factors for local recurrence and distant metastasis were similar, but the local recurrence could not be a significant predictor for distant metastasis. It was indicated that distant metastasis rate was lower in patients with total thyroidectomy in multifocal lesions groups (χ(2)=5.891, P=0.015). Conclusions: Age, tumor size, invaded capsule, bilateral lymph nodes metastasis, multifocal and bilateral lesions are factors for predicting distant metastasis after primary treatment of PTC in children and adolescents. Total thyroidectomy is recommended for patients with multifocal and bilateral lesions.

Association between the X-ray repair cross-complementing group 1 Arg194Trp polymorphism and thyroid carcinoma susceptibility: A meta-analysis

Previous case-control studies having investigated the relationship between the X-ray repair cross-complementing group 1 (XRCC1) Arg194Trp polymorphism and thyroid cancer (TC) have drawn inconsistent conclusions. The current study aimed to clarify the role of this polymorphism in susceptibility to TC. An up-to-date search of PubMed and Web of Science databases was conducted, including articles published up to August 2015. Crude odds ratios (ORs) with 95%CIs were calculated to establish the association between the XRCC1 Arg194Trp polymorphism and TC risk. Five studies were used, comprising 911 patients and 1476 controls. Our meta-analysis indicated that this polymorphism is associated with TC risk in Caucasians (TrpTrp vs ArgArg: OR = 5.72, 95%CI = 1.39-23.54; ArgTrp vs ArgArg: OR = 1.20, 95%CI = 0.87-1.66; dominant model: OR = 1.31, 95%CI = 0.96-1.79; recessive model: OR = 0.18, 95%CI = 0.04-0.73). This investigation demonstrates that the XRCC1 Arg194Trp polymorphism constitutes a risk factor for TC in Caucasian individuals.

Thyroxine control of pancreatic amylase gene expression: modulation of PTF1 binding activity

The role of pancreas specific transcription factor (PTF1) in thyroxine (T4) modulation of amylase gene expression in suckling rats was evaluated. Electrophoretic mobility shift assay (EMSA) was used to determine the PTF1 binding activity by the amount of a synthetic oligonucleotide containing the amylase enhancer sequence bound by nuclear protein extracts. Nuclear protein from rat pancreata showed a developmental increase of PTFI activity correlated with age. To study the action of T4, pups were made hyperthyroid by T4 injection and hypothyroid by feeding propylthiouracil (PTU) to the lactating dams. EMSA of nuclear proteins isolated from these groups showed an increase in PTF1 binding activity in the T4 group and a decrease in the PTU group. Concomitantly, T4 increased, while PTU decreased both amylase enzyme and mRNA concentrations. T4 replacement reversed the effect of PTU on PTF1 binding, amylase enzyme activity and mRNA levels. To examine the age dependence of T4 effects, T4 was injected to pups for 5 days prior to killing at the age of 15, and 25 days. T4 was effective when given at an earlier age (15 days) but not at a later stage (25 days) in increasing amylase activity and amylase mRNA levels. Nuclear proteins isolated from pancreata of these groups showed an increase in PTF1 binding activity in the T4-treated 15-day-olds but not in the 25-day-olds in comparison to their corresponding age matched littermates. These results suggest that PTF1 is an important intermediary in T4 modulation of amylase gene expression during ontogeny of the rat exocrine pancreas.