ABSTRACT
BACKGROUND: The etiology of sinonasal inverted papilloma (IP) is unknown. This study was designed to evaluate the possible risk factors associated with IP Methods: This is a case-control epidemiology study in a tertiary referral center. Fifty patients with IP and 150 matched controls were interviewed using a questionnaire on suspected risk factors. Univariate analysis of the risk factors and calculation of the matched odds ratios, the corresponding 95% CIs, and p values was performed. Significant risk factors were further studied using conditional logistic regression analysis. RESULTS: Outdoor and industrial occupations were associated with IP. Tobacco smoking, drinking alcohol, history of allergic rhinitis, sinusitis, nasal polyp, non-sinonasal papilloma and non-sinonasal malignancy were not significant factors. CONCLUSION: Outdoor and industrial occupations were associated with IP and may be potential risk factors. Future studies are warranted to further evaluate the individual type of occupation and chemical involved.
ABSTRACT
Metallothionein (MT) isoforms have not been studied in papillary thyroid cancer. We examined how the functional MT1 and MT2 isoforms were expressed in papillary thyroid cancer (KAT5) cells. We demonstrated that KAT5 cells expressed eight functional MT1 and MT2 isoforms induced by cadmium. Elevated calcium and activated ERK1/2 predated MT expression. The inhibition of either calcium or ERK1/2 significantly blocked the isoform expression. The induction of these isoforms accompanied an increased progression of cell cycle from G0/G1 to G2-M. The alternation in cell cycle disappeared when the expression of MT isoforms was blocked by calcium inhibitor or ERK1/2 inhibitor. Collectively, KAT5 cells express eight functional MT1 and MT2 isoforms in a pathway controlled by calcium and ERK1/2. The elevation of the MT isoforms contributes to the decreased G0/G1 but increased G2-M phase. These results reveal a novel pathway for the expression of the functional MT in papillary thyroid cancer.
