A case of odontogenic keratocyst in the buccal space: characterization by multimodality imaging including computed tomography, diffusion-weighted magnetic resonance imaging, and ultrasonography.

Odontogenic keratocyst (OKC) is a relatively common non-inflammatory jaw lesion. OKC is known to occur most often in the mandibular angle and mandibular ramus, but rarely outside the bone. In this report, we describe characteristic multimodality imaging of OKC in the buccal space, especially diffusion-weighted MR imaging (DWI) with apparent diffusion coefficient (ADC) mapping, extra-oral and intra-oral ultrasonography. On clinical examination, an approximately 20 mm in diameter mass with elastic hardness was found the left side of the buccal area. Contrast-enhanced CT showed areas of internal non-contrast lesions in the left buccal space. On T1-weighted image, the mass showed multilocular high signal intensity, and homogeneous internal. T2-weighted images revealed high signal at the marginal part and slightly median signal in the internal part. STIR images revealed a heterogeneous high signal in the interior. Furthermore, DWI and ADC map showed high signal and moderate-to-low signal intensity, respectively. ADC value of the lesion was 1.55 × 10-3 mm2 s-1. On extra-oral ultrasonography, the tumor showed clear boundary, hypoechoic, homogeneous internal architecture and vascular signals, and heterogeneous hard of the lesion. On intra-oral ultrasonography also showed clear boundary, hypoechoic, homogeneous internal architecture, heterogeneous hard of the tumor, and back echo enhance. The histopathologic diagnosis based on a full excisional specimen was odontogenic keratocyst. This case suggests that multimodality imaging, especially MR imaging with ADC and DWI, and extra and intra-oral ultrasonography with color Doppler imaging and elastography, could be effective for evaluating buccal lesions.

Clinical study on collagen gel droplet-embedded culture drug sensitivity test for multidrug combination chemotherapy and super selective intra-arterial infusion chemoradiotherapy in oral squamous cell carcinoma.

Using trace three-dimensional culture, the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) can be tested even in cases with a small number of cells, including oral squamous cell carcinoma (OSCC), and evaluation of the antitumor effect with a drug concentration close to the in vivo level is possible. The present report aimed to evaluate the utility of the CD-DST in the assessment of the in vitro efficacy of single-agent and multidrug combination chemotherapy for OSCC in comparison with the clinical response rates and to examine the possible clinical application of CD-DST for such cases. A total of 33 OSCC patients from whom 33 samples were obtained from January 2010 to September 2015 were included. CD-DST was performed, individually and in combination, on the three drugs [i.e., cisplatin (CDDP), 5-fluorouracil (5-FU), and docetaxel (DOC)] and on super selective intra-arterial infusion chemoradiotherapy (IACRT). The overall evaluable rate of the CD-DST in OSCC was 81.8% (27 of 33 cases) and the sensitivity to each anticancer drug was evaluated. The in vitro efficacy rates of IACRT, cisplatin + 5-fluorouracil, and docetaxel + cisplatin + 5-fluorouracil (TPF) confirmed the estimated clinical response rates. In 14 of 33 patients, the results of CD-DST were compared with clinical efficacy, which was judged based on measurable lesions on imaging. For TPF therapy, the sensitivity test of the IACRT had a positive predictive value of 90.9% (10 of 11 cases) and a negative predictive value of 100% (3 of 3 cases); the accuracy of the susceptibility test for the anticancer agents was 92.8% (13 of 14 cases). The CD-DST may be useful in selecting multidrug combination chemotherapy and IACRT for OSCC, however, accumulation of further clinical data is required in the future.

Experimental study of antiangiogenic gene therapy targeting VEGF in oral cancer.

It is well known that tumor angiogenesis plays an important role in local growth and metastasis of oral cancer; therefore, inhibiting angiogenesis is considered to be effective for treating oral cancer. This study aimed to investigate the effectiveness of systemically available antiangiogenic gene therapy targeting vascular endothelial growth factor (VEGF), which is one of the most important angiogenesis accelerators. We administered a soluble form of VEGF receptor-expressing gene incorporated into adenovirus (AdVEGF-ExR) intraperitoneally to nude mice to which oral cancer cell lines (SAS, HSC-3, and Ca9-22) had been transplanted subcutaneously in vivo to inhibit angiogenesis and tumor proliferation. Then, we measured tumor volumes over time, and tumors were enucleated and examined histopathologically and immunohistologically at 28 days after AdVEGF-ExR administration. Compared to the controls to which we administered AdLacZ or saline, significant antiproliferative effects were observed (P < 0.05) in the AdVEGF-ExR administration group, and extensive tumor necrosis was found histopathologically. Immunohistochemical analysis with CD34 (NU-4A1) revealed tumor angiogenesis was suppressed significantly (P < 0.05), and that with ssDNA revealed apoptosis induction was significantly high (P < 0.05) in the AdVEGF-ExR group. However, analysis with Ki-67 (MIB-1) revealed tumor proliferative capacity was not significantly different between the groups. Consequently, we consider that AdVEGF-ExR administration achieved tumor growth suppression by inhibiting angiogenesis and inducing apoptosis, but not by inhibiting the proliferative capacity of tumor cells. Neither topical administration of a soluble form of VEGF receptor (sVEGFR) to the tumor nor a megadose was needed to achieve this inhibition effect. These results suggest gene therapy via sVEGFR would be an effective oral cancer therapy and benefit future clinical applications.