RESUMEN
The purpose of this study was to explore conventional, diffusion, and dynamic contrast-enhanced MRI (DCE-MRI) characteristics for differentiating metaplastic Warthin's tumor (MWT) from other tumor types of the parotid gland, including non-metaplastic Warthin's tumor (non-MWT), pleomorphic adenoma (PA), and malignant tumor (MT). A total of 178 patients with histologically proven tumors of the parotid gland, including 21 MWTs, 49 non-MWTs, 66 PAs, and 42 MTs, were enrolled in the study. Conventional MRI was performed in all patients. One hundred and fifty patients had preoperative diffusion-weighted MR imaging (DWI), and 62 patients had preoperative DCE-MRI. The differences in the conventional, DCE-MRI, and DWI records between MWTs and the other three tumor types were statistically evaluated. Compared with non-MWTs and PAs, there was a statistically significant difference in circumscription (p < 0.01). The ill-defined circumscription was more common in MWTs than non-MWTs and PAs. Compared with PAs, there was a statistically significant difference in morphology (p < 0.05). The lobulated morphology was more common in PAs than MWTs. Compared with PAs and MTs, there was a statistically significant difference in the T2 signal of the solid component (p < 0.01). The T2 moderate intensity of solid components was more common in MWTs than PAs and MTs. The solid components of PAs mostly showed hyperintense on T2-weighted imaging. Cyst/necrosis was more common in MWTs than PAs and MTs. Hyperintense of cyst/necrosis was more common in MWTs and non-MWTs. With respect to contrast enhancement, 52.4% MWTs exhibited moderate or marked enhancement, and most non-MWTs (81.6%) exhibited mild enhancement. Most PAs (84.8%) exhibited marked enhancement. The mean ADC value of MWTs (0.94 × 10-3 ± 0.11 mm2/s) was signiï¬cantly lower than that of the PAs (1.60 × 10-3 ± 0.17 mm2/s) (p < 0.001). On DCE-MRI, six of eight MWTs demonstrated TIC of type B. Although MWT is rare, conventional MRI characteristics, DWI and DCE-MRI can provide useful information for differentiating MWT from other parotid mass.
Asunto(s)
Adenolinfoma , Quistes , Neuroblastoma , Neoplasias de la Parótida , Adenolinfoma/diagnóstico por imagen , Adenolinfoma/patología , Quistes/patología , Diagnóstico Diferencial , Humanos , Imagen por Resonancia Magnética/métodos , Metaplasia/patología , Necrosis/patología , Neuroblastoma/patología , Glándula Parótida/diagnóstico por imagen , Glándula Parótida/patología , Neoplasias de la Parótida/diagnóstico por imagen , Neoplasias de la Parótida/patología , Estudios RetrospectivosRESUMEN
Chemotherapy resistance frequently drives tumor progression. However, the underlying molecular mechanisms remain unclear. In this study, we found that the expression level of miR-26b was down-regulated in the human colorectal cancer tissues and the resistant cells strains: HT-29/5-FU and LOVO/5-FU cells. Meanwhile, we showed that miR-26b improved sensibility of colorectal cancer cells to 5-FU in vitro and enhanced the potency of 5-FU in the inhibition of tumor growth in vivo. We further demonstrated that the tumor suppressive role of miR-26b was mediated by negatively regulating P-glycoprotein (Pgp) protein expression. Furthermore, studies of colorectal cancer specimens indicated that the expression of miR-26b and Pgp had inverse correlation. Importantly, we found that CpG islands in the miR-26b promoter region were hypermethylated in 5-FU resistant cells. Our study is the first to identify the tumor suppressive role of over-expressed miR-26b in chemo-sensitivity. Identification of a novel miRNA-mediated pathway that regulates chemo-sensitivity in colorectal cancer will facilitate the development of novel therapeutic strategies in the future.