Probes for PTEN

KLK4::KLKP1 fusion is a recently described pseudogene that is enriched in prostate cancer (PCa). This new biomarker has not been characterized in the Middle Eastern population.To establish the incidence and prognostic value of KLK4::KLKP1 fusion in a cohort of Middle Eastern men with PCa and explore the relationship of this marker to other relevant biomarkers (PTEN, ERG, SPINK1).We interrogated a cohort of 340 Middle Eastern men with localized PCa treated by radical prostatectomy between 2005 and 2015. KLK4::KLKP1 fusion status was assessed by RNA Chromogenic in situ hybridization (CISH) and correlated to pathological and clinical parameters.RNA-CISH expression of KLK4::KLKP1 was correlated with prognostic factors, ERG, PTEN, and SPINK1 expression, and biochemical recurrence (BCR) following prostatectomy.51.7% of patient samples showed positive KLK4::KLKP1 expression; more commonly in cores of PCa (38%) versus non-cancer (20.6%) (p < 0.0001) and in lower Gleason Grade Group tumors (1-3) vs (4-5). KLK4::KLKP1 expression positively correlated with ERG positivity and inversely associated with PTEN loss. No significant association was found with SPINK1 expression, seminal vesicle invasion, positive surgical margin, pathological stage, or patient age (< 50 or ≥ 50). The association between PTEN loss and BCR increased when combined with KLK4::KLKP1 negativity (HR 2.31, CI 1.03-5.20, p = 0.042).KLK4::KLKP1 expression is more common in this cohort of Middle Eastern men than has been reported in North American men. It is associated with ERG positivity and inversely correlated with PTEN loss. In isolation, KLK4::KLKP1 expression was not significantly associated with clinical outcome or pathological parameters. However, its expression is associated with certain molecular subtypes (ERG-positive, PTEN-intact) and as we demonstrate may help further stratify the risk of recurrence within these groups.

The emergence of castration resistant prostate cancer is associated with a high mortality and remains an area of unmet clinical need. We recently identified a rare subpopulation of normal prostate progenitor cells, characterized by an intrinsic resistance to androgen-deprivation and marked by the expression of LY6D. We here describe the underlying mechanisms driving castration-resistance of LY6D+ luminal progenitors and their contribution to advanced prostate cancer. We demonstrate that conditional deletion of PTEN in the murine prostate epithelium causes an expansion of transformed LY6D+ progenitor cells in proximal and distal regions of the prostate without impairing stem cell properties. Transcriptomic analyses of LY6D+  luminal cells identified an autocrine positive feed-back loop, based on the secretion of amphiregulin (AREG), further increasing cellular fitness and organoid formation. Pharmacological interference with AREG-activated MAPK-signaling overcomes the castration-resistant properties of LY6D+ cells with a near complete suppression of organoid formation. Notably, LY6D+  tumor cells are enriched in prostate specimens from high-grade and androgen-resistant prostate cancer, providing clinical evidence for their contribution to advanced and also metastatic disease. Our data indicate that the prospective identification of LY6D+ cells could allow for an early interference with MAPK-inhibitors to prevent the emergence of castration-resistant prostate cancer.

Primary female urethral carcinoma (PUC-F) accounts for less than 1% of all genitourinary malignancies and comprises a histologically diverse group of tumors that are usually associated with poor prognosis. The carcinomas documented at this site include adenocarcinoma (clear cell adenocarcinoma, columnar cell carcinoma, and Skene gland adenocarcinoma), urothelial carcinoma (UCa), and squamous cell carcinoma (SCC). Recent studies have shown adenocarcinomas to be the most common type of primary urethral carcinoma in females. As most of the urethral carcinomas morphologically resemble carcinomas arising from surrounding pelvic organs or metastases, these should be ruled out before making the diagnosis of PUC-F. These tumors are currently staged according to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. However, the AJCC system has limitations, including the staging of tumors involving the anterior wall of the urethra. Staging systems like the recently proposed histology-based female urethral carcinoma staging system (UCS) takes into account the unique histological landmarks of the female urethra to better stratify pT2 and pT3 tumors into prognostic groups, that correlate with clinical outcomes including recurrence rates, disease-specific survival and overall survival. Further larger multi-institutional cohorts are however required to validate the results of this staging system. There is very limited information regarding the molecular profiling of PUC-F. Thirty-one percent of clear cell adenocarcinomas have been reported to show PIK3CA alterations, whereas 15% of adenocarcinomas show PTEN mutations. Higher tumor mutational burden and PD-L1 staining have been reported in UCa and SCC. Although multimodality treatment is usually recommended in locally advanced and metastatic disease, the role of immunotherapy and targeted therapy is promising in select PUC-F cases.

Primary female urethral carcinoma (PUC-F) accounts for less than 1% of all genitourinary malignancies and comprises a histologically diverse group of tumors that are usually associated with poor prognosis. The carcinomas documented at this site include adenocarcinoma (clear cell adenocarcinoma, columnar cell carcinoma and Skene gland adenocarcinoma), urothelial carcinoma (UCa) and squamous cell carcinoma (SCC). Recent studies have shown adenocarcinomas to be the most common type of primary urethral carcinoma in females. Since most of the urethral carcinomas morphologically resemble carcinomas arising from surrounding pelvic organs or metastases, these should be ruled out before making the diagnosis of PUC-F. These tumors are currently staged according to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. However, the AJCC system has limitations, including the staging of tumors involving the anterior wall of the urethra. Staging systems like the recently proposed histology based female urethral carcinoma staging system (UCS) takes into account the unique histological landmarks of the female urethra to better stratify pT2 and pT3 tumors into prognostic groups, that correlate with clinical outcomes including recurrence rates, disease-specific and overall survival. Further larger multi-institutional cohorts are however required to validate the results of this staging system. There is very limited information regarding the molecular profiling of PUC-F. 31% of clear cell adenocarcinomas have been reported to show PIK3CA alterations, while 15% of adenocarcinomas show PTEN mutations. Higher tumor mutational burden (TMB) and PD-L1 staining have been reported in UCa and SCC. Although multimodality treatment is usually recommended in locally advanced and metastatic disease, the role of immunotherapy and targeted therapy is promising in select PUC-F cases.

Peribiliary glands (PBGs), clusters of epithelial cells residing in the submucosal compartment of extrahepatic bile ducts, have been suggested as biliary epithelial stem/progenitor cell niche; however, evidence to support this claim is limited due to a lack of PBG-specific markers. We therefore sought to identify PBG-specific markers to investigate the potential role of PBGs as stem/progenitor cell niches, as well as an origin of cancer. We examined the expression pattern of the Wnt target gene Axin2 in extrahepatic bile ducts. We then applied lineage tracing to investigate whether Axin2-expressing cells from PBGs contribute to biliary regeneration and carcinogenesis using Axin2-CreERT mice. Wnt signaling activation, marked by Axin2, was limited to PBGs located in the periampullary region. Lineage tracing revealed that Axin2-expressing periampullary PBG cells are capable of self-renewal and supplying new biliary epithelial cells (BECs) to the luminal surface. Additionally, the expression pattern of Axin2 and the mature ductal cell marker CK19 was mutually exclusive in periampullary region, and fate tracing of CK19+ luminal surface BECs revealed gradual replacement by CK19- cells, further supporting the continuous replenishment of new BECs from PBGs to the luminal surface. We also found that Wnt signal enhancer R-spondin3 secreted from Myh11-expressing stromal cells, corresponding to human sphincter of Oddi, maintained the periampullary Wnt signal-activating niche. Notably, introduction of PTEN deletion into Axin2+ PBG cells, but not CK19+ luminal surface BECs, induced ampullary carcinoma whose development was suppressed by Wnt inhibitor. A specific cell population receiving Wnt-activating signal in periampullary PBGs functions as biliary epithelial stem/progenitor cells and also cellular origin of ampullary carcinoma.

Glycine transporters (GlyT1 and GlyT2) that regulate levels of brain glycine, an inhibitory neurotransmitter with co-agonist activity for NMDA receptors (NMDARs), have been considered to be important targets for the treatment of brain disorders with suppressed NMDAR function such as schizophrenia. However, it remains unclear whether other amino acid transporters expressed in the brain can also regulate brain glycine levels and NMDAR function. Here, we report that SLC6A20A, an amino acid transporter known to transport proline based on in vitro data but is understudied in the brain, regulates proline and glycine levels and NMDAR function in the mouse brain. SLC6A20A transcript and protein levels were abnormally increased in mice carrying a mutant PTEN protein lacking the C terminus through enhanced β-catenin binding to the Slc6a20a gene. These mice displayed reduced extracellular levels of brain proline and glycine and decreased NMDAR currents. Elevating glycine levels back to normal ranges by antisense oligonucleotide-induced SLC6A20 knockdown, or the competitive GlyT1 antagonist sarcosine, normalized NMDAR currents and repetitive climbing behavior observed in these mice. Conversely, mice lacking SLC6A20A displayed increased extracellular glycine levels and NMDAR currents. Lastly, both mouse and human SLC6A20 proteins mediated proline and glycine transports, and SLC6A20 proteins could be detected in human neurons. These results suggest that SLC6A20 regulates proline and glycine homeostasis in the brain and that SLC6A20 inhibition has therapeutic potential for brain disorders involving NMDAR hypofunction.