surface plasmons ͉ SEIRA ͉ surface enhancements ͉ near-field effects ͉ infrared absorption spectroscopy

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Fourier-transform infrared difference spectroscopy has been used to detect the vibrational modes in the chromophore and protein that change in position or intensity between rhodopsin and the photoproducts formed at low temperature (70 K), bathorhodopsin and isorhodopsin. A method has been developed to obtain infrared difference spectra between rhodopsin and bathorhodopsin, bathorhodopsin and isorhodopsin, and rhodopsin and isorhodopsin. To aid in the identification of the vibrational modes, we performed experiments on deuterated and hydrated films of native rod outer segments and rod outer segments regenerated with either retinal containing 13C at carbon 15 or 15-deuterioretinal. Our infrared measurements provide independent verification of the resonance Raman result that the retinal in bathorhodopsin is distorted all-trans. The positions of the C = N stretch in the deuterated pigment and the deuterated pigments regenerated with 11-cis-15-deuterioretinal or 11-cis-retinal containing 13C at carbon 15 are indicative that the Schiff-base linkage is protonated in rhodopsin, bathorhodopsin, and isorhodopsin. Furthermore, the C = N stretching frequency occurs at the same position in all three species. The data indicate that the protonated Schiff base has a C = N trans conformation in all three species. Finally, we present evidence that, even in these early stages of the rhodopsin photosequence, changes are occurring in the opsin and perhaps the associated lipids.

The success of crizotinib in ALK-positive patients has elicited efforts to find new oncogenic fusions in lung cancer. These efforts have led to the discovery of novel oncogenic fusion genes such as ROS1 and RET. However, the molecular and clinicopathologic characteristics associated with RET or ROS1 fusion, compared with ALK fusion-positive lung cancer, remain unclear. We accordingly analyzed the clinicopathologic characteristics of RET-and ROS1-fusion-positive lung adenocarcinomas. We further performed immunohistochemistry and fluorescence in situ hybridization analysis (FISH) in 15 cases of RET and 9 cases of ROS1 fusion tumors by identified NanoString's nCounter screening. RET fusion-positive patients were younger in age, never-smokers, and in early T stage; ROS1 fusion-positive patients had a higher number of never-smokers compared with patients with quintuple-negative (EGFR À /KRAS À /ALK À /ROS1 À /RET À ) lung adenocarcinoma. Histologically, RET and ROS1 fusion tumors share the solid signet-ring cell and mucinous cribriform pattern, as previously mentioned in the histology of ALK fusion tumors. Therefore, it can be presumed that fusion gene-associated lung adenocarcinomas share similar histologic features. In immunohistochemistry, the majority of 15 RET and 9 ROS1 fusion-positive cases showed positivity of more than moderate intensity and cytoplasmic staining for RET and ROS1 proteins, respectively. In FISH, the majority of RET and ROS1 rearrangement showed two signal patterns such as one fusion signal and two separated green and orange signals (1F1G1O) and an isolated 3 0 green signal pattern (1F1G). Our study has provided not only characteristics of fusion gene-associated histologic features but also a proposal for a future screening strategy that will enable clinicians to select cases needed to be checked for ROS1 and RET rearrangements based on clinicohistologic features.

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PurposeOropharyngeal squamous cell carcinoma (OSCC) has been recognized as an immunosuppressive disease. Various mechanisms have been proposed for immune escape, including dysregulation of immune checkpoints such as the PD-1:PD-L1 pathway. We investigated the expression of programmed cell death-ligand 1 (PD-L1) in HPV-negative and HPV-positive OSCC to determine its prevalence and prognostic relevance.Materials and MethodsUsing immunohistochemistry, 133 cases of OSCC were evaluated for expression of PD-L1. Formalin-fixed paraffin-embedded tumor samples were stained with monoclonal antibody (clone 5H1) to PD-L1. PD-L1 positivity was defined as membrane staining in ≥20% of tumor cells. Correlations between PD-L1 expression and HPV status and survival parameters were analyzed.ResultsOf the 133 patients, 68% showed PD-L1 expression, and 67% of patients were positive for p16 expression by immunohistochemistry. No significant difference in PD-L1 expression was observed between HPV(-) and HPV(+) tumors (61% vs. 71%, p=0.274). No significant difference in age, gender, smoking history, location of tumor origin, or stage was observed according to PD-L1 status. With a median follow-up period of 44 months, older age (≥65) (p=0.017) and T3-4 stage (p<0.001) were associated with poor overall survival (OS), whereas PD-L1 expression did not affect OS in univariate and multivariate analysis.ConclusionPD-L1 expression was observed in the majority of OSCC patients regardless of HPV status. Further large prospective studies are required to determine the role of PD-L1 expression as a prognostic or predictive biomarker, and clinical studies of immune checkpoint inhibitors in OCSS are warranted regardless of HPV status.