PCSK2 expression in neuroendocrine tumors points to a midgut, pulmonary, or pheochromocytoma-paraganglioma origin.

Neuroendocrine tumors (NETs) are often diagnosed from the metastases of an unknown primary tumor. Specific immunohistochemical (IHC) markers indicating the location of a primary tumor are needed. The proprotein convertase subtilisin/kexin type 2 (PCSK2) is found in normal neural and neuroendocrine cells, and known to express in NETs.

Treponema denticola chymotrypsin-like protease as associated with HPV-negative oropharyngeal squamous cell carcinoma.

Background: An opportunistic oral pathogen, Treponema denticola (Td), has been linked to orodigestive carcinogenesis, but its role in oropharyngeal squamous cell carcinoma (OPSCC) has remained open. We evaluated the presence of Td chymotrypsin-like protease (Td-CTLP) in a series of 201 unselected consecutive OPSCC patients, and the relation of the Td-CTLP to human papillomavirus (HPV) status, to expression of toll-like receptors (TLR) 5, 7, and 9, and to clinical parameters and patient outcome.

Methods: Clinicopathological data came from hospital registries.

Toll-like receptor 5 and 7 expression may impact prognosis of HPV-positive oropharyngeal squamous cell carcinoma patients.

A large subset of oropharyngeal squamous cell carcinomas (OPSCCs) is associated with HPV infection and has better outcome than non-viral-related tumors. Various malignancies also carry a role for TLRs, key activators of inflammation and innate immunity. We examined the expression of TLRs in OPSCC, and their association with HPV status and treatment outcome.

Grading of neuroendocrine tumors with Ki-67 requires high-quality assessment practices.

Gastrointestinal and pancreatic neuroendocrine tumors (NETs) arise from disseminated neuroendocrine cells, expressing general and specific neuroendocrine markers. The World Health Organization 2010 classification of NETs is based on grading them according to the proliferation index (PI), which is determined by immunohistochemical staining of the nuclear antigen Ki-67. The classification introduces Ki-67 as the most important criterion for tumor grading, influencing patients' prognoses and the choice of treatment.