Altered cadherin expression is important for metastasis in many carcinomas including head and neck squamous cell carcinoma (SCC). We evaluated E- and N-cadherin expression specifically in oropharyngeal SCC and correlated this with clinical and pathologic features. Oropharyngeal SCC patients with clinical follow up information were identified from clinician databases from 1996 through 2007 and tissue microarrays created. Tumors had been previously typed histopathologically as keratinizing, non-keratinizing, or non-keratinizing with maturation, and had known p16 and human papillomavirus status, respectively. Immunohistochemistry was performed on the microarrays, and staining was evaluated for presence and intensity (0 = negative, 1 = weak, 2 = moderate, 3 = strong) both visually and also with digital image analysis software. Of 154 cases, E-cadherin was expressed in 152 (98.7%) and N-cadherin in 17 (11.5%). Neither E- nor N-cadherin expression was statistically significantly associated with histopathologic type (P = 0.082 and P = 0.228, respectively). E-cadherin staining intensity was not statistically significantly associated with nodal or distant metastasis, either visually or by image analysis, (P = 0.098 and P = 0.963 respectively) nor was N-cadherin (P = 0.228 and P = 0.935 respectively). Neither E- nor N-cadherin expression was associated with death from disease (P = 0.995; P = 0.964, respectively). E-cadherin is extensively expressed by oropharyngeal SCC, even the non-keratinizing type. Our results suggest that cadherin expression may not be a predictor for nodal or distant metastasis in these tumors. Mechanisms independent of cadherin expression may be important for metastases in oropharyngeal SCC.

elevated plus maze tests. The highly hippocampal-dependent object placement (OP) test (a.k.a. novel object location test) was used to assess spatial memory dependent on intact neural stem cell function. Two OP tests, one with 40 min retention interval, and one with a more challenging 70 min retention interval were performed. An object recognition (OR) test was used to test hippocampal-independent cognitive function. The results were determined based on previously validated pass/fail criteria. Differences among treatment groups were analyzed using a likelihood ratio test for chi-square distributions, and pairwise chi-square comparisons were used to assess pairwise differences. Results: The irradiation procedure was well tolerated by all animals and all groups performed similarly on the general behavior tasks. Table 1 shows the results for the OP and OR behavior tasks. Animals exposed to WBRT showed significant deficits compared to sham-irradiated controls in the OP 40 min task (P Z .039) and the OP 70 min task (P Z .030). In contrast, HSI mice did not perform significantly different from control mice at either the 40 min (P Z .956) or 70 min (P Z .459) retention interval and performed significantly better compared to WBRT mice in the OP 40 min task (P Z .032). No difference between groups was found in the hippocampal-independent OR task (P Z .699). Conclusion: The results of this study show that hippocampal-dependent spatial memory is clearly affected after WBRT, but preserved in animals receiving HSI, consistent with the result seen in the RTOG 0933 clinical trial in humans. As such, this animal model could prove a helpful tool for researchers exploring novel strategies for mitigating the adverse cognitive impairment of high-dose cranial irradiation.