The 2022 World Health Organization Classification of Tumours of the Urinary System and Male Genital Organs-Part A: Renal, Penile, and Testicular Tumours

The fifth edition of the World Health Organization (WHO) classification of urogenital tumours (WHO "Blue Book"), published in 2022, contains significant revisions. This review summarises the most relevant changes for renal, penile, and testicular tumours. In keeping with other volumes in the fifth edition series, the WHO classification of urogenital tumours follows a hierarchical classification and lists tumours by site, category, family, and type. The section "essential and desirable diagnostic criteria" included in the WHO fifth edition represents morphologic diagnostic criteria, combined with immunohistochemistry and relevant molecular tests. The global introduction of massive parallel sequencing will result in a diagnostic shift from morphology to molecular analyses. Therefore, a molecular-driven renal tumour classification has been introduced, taking recent discoveries in renal tumour genomics into account. Such novel molecularly defined epithelial renal tumours include SMARCB1-deficient medullary renal cell carcinoma (RCC), TFEB-altered RCC, Alk-rearranged RCC, and ELOC-mutated RCC. Eosinophilic solid and cystic RCC is a novel morphologically defined RCC entity. The diverse morphologic patterns of penile squamous cell carcinomas are grouped as human papillomavirus (HPV) associated and HPV independent, and there is an attempt to simplify the morphologic classification. A new chapter with tumours of the scrotum has been introduced. The main nomenclature of testicular tumours is retained, including the use of the term "germ cell neoplasia in situ" (GCNIS) for the preneoplastic lesion of most germ cell tumours and division from those not derived from GCNIS. Nomenclature changes include replacement of the term "primitive neuroectodermal tumour" by "embryonic neuroectodermal tumour" to separate these tumours clearly from Ewing sarcoma. The term "carcinoid" has been changed to "neuroendocrine tumour", with most examples in the testis now classified as "prepubertal type testicular neuroendocrine tumour".

Stimulation of the epidermal growth factor receptor induces glial-specific protein expression in the human DAOY neuroectodermal cell line

Central nervous system (CNS) stem cells require epidermal growth factor (EGF) to survive and express glial-specific proteins (GSPs) under its influence. EGF and its receptor (EGF-R) therefore are involved in gliogenesis. We hypothesize that EGF selectively modulates GSP expression in pluripotential CNS cells and this effect is dependent on the degree of EGF-R activation (i.e., the amount of both EGF and the EGF-R present). In order to explore this, we investigated the effects of EGF on the expression of glial- and neuronal-specific proteins in the pluripotential human neuroectodermal cell line, DAOY. DAOY clones expressing different EGF-R levels were treated with EGF. The expression of glial fibrillary acid protein (GFAP), glutamine synthetase (GS) and neuron-specific enolase (NSE) were measured by ELISA. In a clone with low EGF-R levels (clone DAOY-YS-15), EGF selectively stimulated GSPs. In cells which express twice the EGF-R level, EGF (10(-8) M) stimulated both glial and neuronal proteins nonspecifically. In cells with higher EGF-R numbers, EGF suppressed both glial and neuronal proteins. These effects were not due to the negligible growth influences of EGF on the cells. In clone DAOY-YS-15, selective GSP expression was observed as early as 2 days after exposure to EGF (10(-9) M). In these cells, GFAP induction was also shown at the transcriptional level using a quantitative reverse transcriptase-polymerase chain reaction. This suggests one mechanism for EGF action. Our findings are therefore consistent with the hypothesis that the selective induction of GSPs in pluripotent cells is dependent on the EGF-R level and the degree of EGF-R activation.

Retroviral transfer of the beta-nerve growth factor gene into murine neuroectodermal tumor cells modulates cell proliferation rate, neurite formation, and NGF binding site expression

The response of wild-type and genetically engineered neuroectodermal tumor (NET) cells to exogenous and endogenously synthesized nerve growth factor (NGF) was investigated. Differences in cell proliferation rate, neurite formation, and expression of NGF binding sites were quantitatively determined. Ecotropic retroviral vectors were used to transfer the genes for beta-galactosidase (beta-GAL) and NGF into wild-type C-1300 and Neuro-2A murine neuroblastoma (MNB) and rat pheochromocytoma (PC-12) cells. Conditioned media obtained from NET cells infected with the NGF gene contained biologically active NGF, whereas media from beta-GAL infected cells did not. Infection with the NGF vector induced a short-term decrease in cell proliferation rate and increased neurite formation in wild-type, substrate-adherent PC-12 and Neuro-2A MNB cells (P > 0.05). Incubation of wild-type C-1300, Neuro-2A MNB, and PC-12 cells with NGF (0-200 ng/ml) for 5 days significantly reduced proliferation rates in a concentration-dependent manner and increased neurite extrusion. All NGF-NET cells had a significantly diminished response to the antiproliferative action of exogenous NGF. Ligand binding assays with 125I-NGF demonstrated a marked reduction in the number of NGF binding sites on NGF-NET cells compared to wild type. The attenuated response of NGF-NET cells to exogenous NGF correlated positively with the down-regulation of NGF binding sites. In conclusion, beta-NGF gene transfer into wild-type NET cells induces the synthesis and secretion of NGF, temporarily decreases cell proliferation rate, increases neurite extrusion, down-regulates NGF binding sites, and reduces NET cell responsiveness to NGF. A putative role for NGF may be the modulation of NET cell proliferation and differentiation.

A possible growth factor role of IL-6 in neuroectodermal tumours

Preliminary data have shown that IL-6 may act as an autocrine growth factor to control proliferation. We further characterised the role of IL-6 in tumour growth as an autocrine/paracrine growth factor in neuroectodermal tumours. We evaluated the production and secretion of IL-6 by seven human melanoma, five neuroblastoma and one glioblastoma cell lines. Moreover, we determined their IL-6-dependent growth in serum free-medium or under minimal growth-supplement conditions: IL-6 dependent growth was observed in two non-IL-6 producing melanoma and in one neuroblastoma cell lines. In addition, expression of IL-6 mRNA and peptide was increased by retinoic acid. The data support the hypothesis that IL-6 contributes to neuroectodermal tumour growth, even though it shows a less potent effect than other reported growth factor such as IGF-II.

HIV-1 infection of primary human neuroblasts

Central nervous system (CNS) disorders are frequent in HIV-1-infected individuals, particularly in newborns and children, and are accompanied by histological alterations resulting in neuronal loss. Although several tumor-derived neuroectodermal cell lines can be infected by HIV-1, it has been reported that primary neural cells cannot be infected after they differentiate. However, pediatric AIDS is often the result of HIV-1 infection occurring during fetal development and early postnatal life, when neural cells are not yet differentiated. Here we show that primary cell cultures derived from the human fetal olfactory system which are representative of the developing CNS can be infected by both HIV-1 strains, the monocyte-macrophagotropic BaL and the lymphotropic HTLV-IIIB, although they do not express the CD4 molecule. In addition, the levels of viral replication are higher with the HIV-1 BaL than with the IIIB isolate. These results suggest that (1) during development immature neurons are susceptible to HIV-1 infection; (2) monocyte-macrophagotropic HIV-1 strains may preferentially be involved in the productive infection of the nervous system; and (3) a mechanism(s) other than the CD4-mediated viral entry is responsible for HIV-1 infection of immature neurons.

Repeated narcosis in a young child

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