Erythropoietin (EPO) has protective effects in neurodegenerative and neuroinflammatory diseases, including in animal models of multiple sclerosis, where EPO decreases disease severity. EPO also promotes neurogenesis and is protective in models of toxic demyelination. In this study, we asked whether EPO could promote neurorepair by also inducing remyelination. In addition, we investigated whether the effect of EPO could be mediated by the classical erythropoietic EPO receptor (EPOR), since it is still questioned if EPOR is functional in nonhematopoietic cells. Using CG4 cells, a line of rat oligodendrocyte precursor cells, we found that EPO increases the expression of myelin genes (myelin oligodendrocyte glycoprotein [MOG] and myelin basic protein [MBP]). EPO had no effect in wild-type CG4 cells, which do not express EPOR, whereas it increased MOG and MBP expression in cells engineered to overexpress EPOR (CG4-EPOR). This was reflected in a marked increase in MOG protein levels, as detected by Western blot. In these cells, EPO induced by 10-fold the early growth response gene 2 (Egr2), which is required for peripheral myelination. However, Egr2 silencing with a siRNA did not reverse the effect of EPO, indicating that EPO acts through other pathways. In conclusion, EPO induces the expression of myelin genes in oligodendrocytes and this effect requires the presence of EPOR. This study demonstrates that EPOR can mediate neuroreparative effects.

Penile cancer is a rare malignancy estimated to affect 26,000 men globally each year. The association with penile cancer, in particular non-invasive disease, and human papilloma virus (HPV) is well known. Ninety-five percent of cases of penile cancer are squamous cell carcinoma (SCC), which are staged using the TNM staging system. Terminology describing the histological appearance of non-invasive penile cancer has changed with all cases grouped under the umbrella term of penile intraepithelial neoplasia (PeIN); either undifferentiated or differentiated. This replaces previous terms such as carcinoma in situ (CIS) and eponymous names such as Bowen’s disease. This change is recognised by the World Health Organisation (WHO). The topical treatments most commonly used for PeIN are 5-fluorouracil (5-FU) and imiquimod (IQ). Other treatments such as photodynamic therapy (PDT) are used but to a lesser degree. The evidence for all of these treatments is heterogenous with no randomised data available. Overall up to 57% complete response has been reported with a low number of serious adverse events. In this article, we aim to review the available evidence for the topical treatment of non-invasive penile cancer specifically regarding its efficacy and toxicity.