Cancer

In situ analysis of biomarkers is highly desirable in molecular pathology because it allows the examination of biomarker status within the histopathological context of clinical specimens. Immunohistochemistry and DNA in situ hybridization (ISH) are widely used in clinical settings to assess protein and DNA biomarkers, respectively, but clinical use of in situ RNA analysis is rare. This disparity is especially notable when considering the abundance of RNA biomarkers discovered through whole-genome expression profiling.

Human papillomavirus (HPV) is associated with oropharyngeal squamous cell carcinomas. Persistent viral infection is postulated to lead to carcinogenesis, although infection of benign adjacent epithelium is not typically observed. It is known that immune evasive tumor cells can provide an ideal niche for a virus. The B7-H1/PD-1 cosignaling pathway plays an important role in viral immune evasion by rendering CD8+ cytotoxic T cells anergic. We hypothesized that HPV-related oropharyngeal squamous cell carcinomas express B7-H1 as a mechanism for immune evasion.

Diagnostics in the field of breast carcinoma are constantly evolving. The recent wave of molecular methodologies, both microscope and non-microscope based, have opened new ways to gain insight into this disease process and have moved clinical diagnostics closer to a 'personalized medicine' approach. In this review we highlight some of the advancements that laboratory medicine technology is making toward guiding the diagnosis, prognosis, and therapy selection for patients affected by breast carcinoma.

Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma has unique biology and better outcomes. p16 immunostaining is used as a surrogate marker for transcriptionally active HPV. Although diffuse staining is generally accepted as positive, the significance of partial staining has not been established, nor has the cutoff for extent of p16 staining that should be used to identify a tumor as HPV-related. From three other large studies utilizing p16 immunohistochemistry, we identified all cases with partial positive staining.

AIMS:

Human papillomavirus is well established in oropharyngeal squamous cell carcinoma as both causative and prognostic, but its significance in non-oropharyngeal tumours is unclear. In particular, the significance of finding viral DNA is not known. We sought to evaluate nonoropharyngeal squamous cell carcinomas for transcriptionally-active human papillomavirus and to compare this with the presence of viral DNA.

METHODS:

Evidence for transcriptional activation of the viral oncoproteins E6 and E7 is regarded as the gold standard for the presence of clinically relevant human papillomavirus (HPV), but detection of E6/E7 mRNA requires RNA extraction and polymerase chain reaction amplification-a challenging technique that is restricted to the research laboratory. The development of RNA in situ hybridization (ISH) probes complementary to E6/E7 mRNA permits direct visualization of viral transcripts in routinely processed tissues and has opened the door for accurate HPV detection in the clinical care setting.

A remarkable feature of regenerative processes is their ability to halt proliferation once an organ's structure has been restored. The Wnt signalling pathway is the major driving force for homeostatic self-renewal and regeneration in the mammalian intestine. However, the mechanisms that counterbalance Wnt-driven proliferation are poorly understood.

Spindle cell carcinoma is an uncommon variant of squamous cell carcinoma characterized by spindled or pleomorphic cells which appear to be a true sarcoma but are actually epithelial. Some head and neck squamous cell carcinoma variants can be human papillomavirus (HPV)-related and have improved outcomes. We sought to determine if spindle cell carcinomas are associated with transcriptionally-active HPV. Cases of spindle cell carcinoma were retrieved from department files.

PCA3 is a prostate-specific non-coding RNA, with utility as a urine-based early detection biomarker. Here, we report the evaluation of tissue PCA3 expression by RNA in situ hybridization in a cohort of 41 mapped prostatectomy specimens. We compared tissue PCA3 expression with tissue level ERG expression and matched pre-prostatectomy urine PCA3 and TMPRSS2-ERG levels. Across 136 slides containing 138 foci of prostate cancer, PCA3 was expressed in 55% of cancer foci and 71% of high-grade prostatic intraepithelial neoplasia foci.

Patient management based on HER2 status in breast carcinoma is an archetypical example of personalized medicine but remains hampered by equivocal testing and intratumoral heterogeneity.