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Background The burden and trend of thyroid cancer in Vietnam have not been well documented. This study aimed to investigate the trends in incidence and histological pattern of thyroid cancer in Ho Chi Minh City from 1996 to 2015. Methods A population-based study retrieved data from the Ho Chi Minh City Cancer Registry during 1996–2015. Trends in the incidence of thyroid cancer were investigated based on age, gender, and histology for each 5-year period. Annual percentage change (APC) in incidence rates was estimated using Joinpoint regression analysis. Results In the study period, there were 5953 thyroid cancer cases (men-to-women ratio 1:4.5) newly diagnosed in Ho Chi Minh City with the mean age of 42.9 years (±14.9 years). The age-standardized incidence rate of thyroid cancer increased from 2.4 per 100,000 during 1996–2000 (95% confidence interval [95% CI]: 2.2–2.6) to 7.5 per 100,000 during 2011–2015 (95% CI: 7.3–7.9), corresponded to an overall APC of 8.7 (95% CI 7.6–9.9). The APC in men and women was 6.2 (95% CI: 4.2–8.2) and 9.2 (95% CI: 8.0–10.4), respectively. The incidence rate in the < 45 years age group was the highest diagnosed overall and increased significantly in both men (APC 11.0) and women (APC 10.1). Both genders shared similar distribution of subtype incidences, with papillary thyroid cancer constituted the most diagnosed (73.3% in men and 85.2% in women). The papillary thyroid cancer observed a markedly increase overall (APC of 10.7 (95% CI 9.3–12.0)). Conclusions There were appreciable increases in the age-standardized incidence rate of thyroid cancer in both genders, mainly contributed by the papillary subtype. The age of patients at diagnosis decreased gradually. The widespread utilization of advanced diagnostic techniques and healthcare accessibility improvement might play a potential role in these trends. Further investigations are needed to comprehend the risk factors and trends fully.

The native envelope gene (env) of Jaagsiekte sheep retrovirus (JSRV) also acts as an oncogene. To investigate the mechanism of transformation, we performed yeast 2-hybrid screening for cellular proteins that interact with Env. Among several candidates, we identified mouse or rat zinc finger protein 111 (zfp111). The interaction between Env and Zfp111 was confirmed through in vivo coimmunoprecipitation assays. Knockdown of endogenous Zfp111 caused a decrease in cell transformation by JSRV Env, while overexpression of Zfp111 increased overall Env transformation, supporting a role for Zfp111 in Env transformation. Knockdown of Zfp111 had no effect on the growth rate of parental rat 208F cells, while it decreased the proliferation rate of JSRV-transformed 208F cells, suggesting that JSRV-transformed cells became dependent on Zfp111. In addition, Zfp111 preferentially bound to a higher-mobility form of JSRV Env that has not been described previously. The higher-mobility form of Env (P70 env ) was found exclusively in the nuclear fraction, and size of its polypeptide backbone was the same as that of the cytoplasmic Env polyprotein (Pr80 env ). The differences in glycosylation between the two versions of Env were characterized. These results identify a novel cellular protein, Zfp111, that binds to the JSRV Env protein, and this binding plays a role in Env transformation. These results indicate that JSRV transformation also involves proteins and interactions in the nucleus. IMPORTANCEThe envelope protein (Env) of Jaagsiekte sheep retrovirus (JSRV) is an oncogene, but its mechanism of cell transformation is still unclear. Here we identified seven candidate cellular proteins that can interact with JSRV Env by yeast two-hybrid screening. This study focused on one of the seven candidates, zinc finger protein 111 (Zfp111). Zfp111 was shown to interact with JSRV Env in cells and to be involved in JSRV transformation. Moreover, coexpression of JSRV Env and Zfp111 led to the identification of a novel nuclear form of the JSRV Env protein that binds Zfp111. Nuclear Env was found to differ by glycosylation from the cytoplasmic Env precursor to the virion envelope proteins. These results suggest that JSRV Env transformation may involve nuclear events such as an alteration in transcription mediated by Env-Zfp111 interactions. Jaagsiekte sheep retrovirus (JSRV) is a betaretrovirus that causes ovine pulmonary adenocarcinoma (OPA), a contagious lung cancer in sheep that reflects malignant transformation of lung secretory epithelial cells (1, 2). OPA is morphologically similar to human lepidic adenocarcinoma, formerly known as bronchioloalveolar carcinoma (more recently designated adenocarcinoma in situ [AIS]) (3), a type of lung cancer that is less associated with cigarette smoke, and it is a good model for this type of human lung cancer (4-6).JSRV is a simple retrovirus that contains the standard retroviral genes gag, pro, pol, and env (7). While JSRV does not carry a transduced cellular oncogene, in experimental inoculation o...