Present and Future of EGFR Inhibitors for Head and Neck Squamous Cell Cancer

Although EGFR is expressed at high levels in head and neck squamous cell carcinomas (HNSCCs) and mutations are extremely rare, monotherapy with EGFR inhibitors has shown limited success. The PI3kinase/Akt pathway is responsible for cellular survival, and inhibition of phosphatidylinositol (PI) synthesis has antiproliferative, anti-invasive, and antiangiogenesis effects on HNSCC. Molecular crosstalk has been observed between EGFR and IGF1R signaling through the PI3kinase/Akt pathway in HNSCC, as has molecular crosstalk between the NFκB and STAT3 signaling pathways. Therefore, the combination of an EGFR antagonist with an agent that inhibits the activation of both Akt and NFκB may overcome resistance to EGFR antagonists in HNSCC

Lambert-Eaton syndrome antibodies inhibit acetylcholine release and P/Q-type Ca2+ channels in electric ray nerve endings

The types of voltage-dependent calcium channels (VDCCs) present in the cholinergic terminals isolated from the electric organ of the ray, Narke japonica, were characterized on the basis of their pharmacological sensitivity to specific antagonists. Inhibition of these channel types by autoantibodies from patients with the Lambert-Eaton syndrome (LES) was then studied to determine the specificity of the pathogenic IgG. In normal untreated synaptosomal preparations, maximal doses of N- and P and/or Q-type Ca2+ channel antagonists, -conotoxin GVIA and -agatoxin IVA, inhibited depolarization-evoked ACh release by 47 % and 43 %, respectively. Calciseptine, an L-type VDCC antagonist, caused a 20 % reduction in the release. This indicates that the exocytotic release process is predominantly mediated by N- and P/Q-type VDCCs. LES IgG or sera caused an inhibition of ACh release by 39-45 % in comparison with the control antibody-treated preparations. The ionomycin-induced ACh release, however, was not altered by the antibodies. Additionally, the same LES antibodies inhibited whole-cell calcium currents (ICa) in bovine adrenal chromaffin cells. Thus, the pathogenic antibodies exert their action on VDCCs present in the synaptosomes. The efficacy of three Ca2+ channel antagonists in blocking ACh release was determined in preparations pretreated with LES IgG. -Agatoxin IVA produced only an additional 3-5 % reduction in release beyond that obtained with LES antibodies. Despite the pretreatment with LES IgG, -conotoxin GVIA and calciseptine inhibited the release to nearly their control levels. These results indicate that LES antibodies mainly downregulate P/Q-type Ca2+ channels which contribute to presynaptic transmitter release from the cholinergic nerve terminals of electric organ. The present findings are consistent with the hypothesis that P/Q-type VDCCs at the neuromuscular junction are the target of LES antibodies and that their inhibition by the antibodies produces the characteristic neuromuscular defect in this disease

Adenomyomatosis Concomitant with Primary Gallbladder Carcinoma

Some clinicians have proposed a relationship between gallbladder (GB) cancer and adenomyomatosis (ADM) of the gallbladder, although the latter condition is not considered to have malignant potential. We retrospectively reviewed the surgical pathology database of patients who underwent resection for ADM of the gallbladder at our institution from March 2005 to May 2015. In total, 624 patients underwent surgical resection of the gallbladder with Rokitansky-Aschoff sinuses. Of these cases, 93 were pathologically diagnosed with ADM of the gallbladder, with 44 (47.3%) classified macroscopically as fundal-type ADM, 26 (28.0%) as segmental type, and 23 (24.7%) as diffuse-type ADM. In 3 of the 93 (3.2%) resected specimens, early-stage GB carcinoma was detected, although preoperative imaging did not suggest a malignant neoplasm of the gallbladder in any of these patients. GB cancer subsequently developed in the mucosa of the fundal compartment distal to the annular stricture of the segmental-type ADM in 2 of these patients and against the background of the fundal-type ADM in 1 patient. This study revealed the difficulty of early diagnosis of primary GB cancer in the setting of concurrent ADM, and clinicians should be aware of this frequent coexistence