Purpose: To evaluate diffusion‐weighted imaging (DWI) for detection of pelvic lymph node metastasis in patients with cervical and uterine cancers.Materials and Methods: Fifty patients scheduled for pelvic lymph node dissection were enrolled for 3T magnetic resonance imaging (MRI) using a single‐shot echo‐planar DWI technique, body‐phased array coil, b = 0, 1000 s/mm². We measured short/long‐axis diameters, mean apparent diffusion coefficient (ADC) values of all identifiable nodes, relative ADC values between tumors and nodes, and utilized their cutoff values to validate the diagnostic accuracy internally. Histopathologic results served as the reference standard.Results: The relative ADC values between tumor and nodes were significantly lower in metastatic than in benign nodes (0.06 vs. 0.21 × 10⁻³ mm²/s, P < 0.001; cutoff value 0.10 × 10⁻³ mm²/s). Compared to conventional MRI, the method combining size and relative ADC values resulted in better sensitivity (25% vs. 83%) and similar specificity (98% vs. 99%). The smallest metastatic lymph node detected by this method measured 5 mm on its short axis.Conclusion: The combination of size and relative ADC values was useful in detecting pelvic lymph node metastasis in patients with cervical and uterine cancers. J. Magn. Reson. Imaging 2008.

To assess the diagnostic accuracy of fused T2-weighted and high-b-value diffusion-weighted (DW) magnetic resonance (MR) images at 3 T for evaluation of myometrial invasion in patients with endometrial cancer. Institutional review board approval and informed consent were obtained. From May 2006 to October 2007, 48 consecutive patients aged 25-80 years (mean age, 57 years) who had endometrial cancer were prospectively enrolled for preoperative evaluation by using a 3-T MR unit. Two radiologists interpreted the depth of myometrial invasion on T2-weighted images, dynamic contrast material-enhanced MR images, and fused T2-weighted and DW MR images (b = 1000 sec/mm(2)). Statistical methods included kappa statistics for reader agreement, Pearson analysis for pathologic correlation, accuracy assessment, and receiver operating characteristic analysis for diagnostic performance comparison. Surgical pathologic findings were the reference standard. Reader agreement was excellent for fused T2-weighted and DW images (weighted kappa, 0.79), with a significant pathologic correlation regarding the depth of myometrial invasion (r = 0.94, P < .0001). For assessing any myometrial involvement, addition of fused T2-weighted and DW imaging to dynamic contrast-enhanced or dynamic contrast-enhanced and T2-weighted imaging was significantly better compared with dynamic contrast-enhanced imaging alone (P < .001) or dynamic contrast-enhanced and T2-weighted (P = .001) imaging; T2-weighted imaging combined with fused T2-weighted and DW imaging also was better than dynamic contrast-enhanced and T2-weighted imaging (P = .001). Tumor apparent diffusion coefficients were 0.60-1.32 x 10(-3) mm(2)/sec (median, 0.75 x 10(-3) mm(2)/sec), with no significant correlation with the depth of myometrial invasion (P = .31, r = -0.15). Fused T2-weighted and high-b-value DW images at 3 T can provide accurate information for preoperative evaluation of myometrial invasion.

MicroRNAs (miRNAs) play important roles in tumorigenesis by regulating oncogenes and tumor-suppressor genes. In this study, miR-187 and miR-200a were found to be expressed at higher levels in ovarian cancers than in benign tumors. In patients with ovarian cancer, however, higher levels of miR-187 and miR-200a expression were paradoxically associated with better OS and recurrence-free survival. Further, multivariate analysis showed that miR-187 served as an independent prognostic factor for patients with ovarian cancer (n=176). Computational prediction and microarray results indicated that miR-187 directly targeted Disabled homolog-2 (Dab2), and luciferase reporter assays confirmed that the target site of miR-187 was located at the 3′-UTR of the Dab2 gene. Generally considered as a tumor-suppressor gene, Dab2 may actually promote tumor progression in advanced cancers through epithelial-to-mesenchymal transition (EMT). Ectopic expression of miR-187 in cancer cells promoted cell proliferation, but continued overexpression of miR-187 suppressed Dab2 and inhibited migration. Suppression of miR-187 upregulated Dab2, which, by inhibiting E-cadherin levels while stimulating vimentin and phospho-FAK levels, promoted EMT. Reduced ovarian cancer Dab2 histoscores correlated with high miR-187 levels and improved outcomes of patients. Collectively, these results demonstrate distinct dual roles of Dab2 in cell proliferation and tumor progression. In the initial steps of tumorigenesis, upregulated miR-187 suppresses Dab2, promoting cell proliferation. During the later stages, however, continued increased levels of miR-187 inhibits the Dab2-dependent EMT that is associated with tumor invasiveness, which is presumed to be the reason why cancers with high miR-187 levels were associated with better survivals.