Search Results (37)

Background: Emerging evidence suggests that biological sex shapes glioma biology and therapeutic response. Methods: We performed a sex-stratified analysis of CGGA (Chinese Glioma Genome Atlas) RNA sequencing data comparing low-grade glioma (LGG) with high-grade glioma (HGG) and glioblastoma (GBM). Using the 3PodR framework, we integrated differential expression analysis with Gene Set Enrichment Analysis (GSEA), EnrichR, leading-edge analysis, and iLINCS drug repurposing. Results: These comparisons provide a proxy for biological processes underlying malignant transformation. In LGG vs. HGG, 973 significantly differentially expressed genes (DEGs) were identified in females and 1236 in males, with 15.5% and 33.5% unique to each sex, respectively. In LGG vs. GBM, 2011 DEGs were identified in females and 2537 in males, with 12.6% and 30.7% being unique. Gene-level contrasts included GLI1 upregulation in males and downregulation in females, GCGR upregulation in males, MYOD1 upregulation in females, and HIST1H2BH downregulation in males. Additional top DEGs included PRLHR, DGKK, DNMBP-AS1, HOXA9, CTB-1I21.1, RP11-47I22.1, HPSE2, SAA1, DLK1, H19, PLA2G2A, and PI3. In both sexes, LGG–HGG and LGG–GBM grade comparisons converged on neuronal and synaptic programs, with enrichment of glutamatergic receptor genes and postsynaptic modules, including GRIN2B, GRIN2A, GRIN2C, GRIN1, and CHRNA7. In contrast, collateral pathways diverged by sex: females showed downregulation of mitotic and chromosome-segregation programs, whereas males showed reduction of extracellular matrix and immune-interaction pathways. Perturbagen analysis nominated signature-reversing compounds across sexes, including histone deacetylase inhibitors, Aurora kinase inhibitors, microtubule-targeting agents such as vindesine, and multi-kinase inhibitors targeting VEGFR, PDGFR, FLT3, PI3K, and MTOR. Conclusions: Glioma grade comparisons reveal a shared neuronal–synaptic program accompanied by sex-specific transcriptional remodeling. These findings support sex-aware therapeutic strategies that pair modulation of neuron–glioma coupling with chromatin- or receptor tyrosine kinase/angiogenic-targeted agents, and they nominate biomarkers such as GLI1, MYOD1, GCGR, PRLHR, and HIST1H2BH for near-term validation. Full article

Background/Objective: The vascular endothelial growth factor (VEGF) signaling pathway induces angiogenesis, which impacts tumor progression and clinical outcomes in patients with localized osteosarcoma. This study evaluates whether genetic polymorphisms in the VEGF signaling pathway are associated with survival outcomes in these patients. Methods: Sixty-nine patients with localized high-grade osteosarcoma enrolled in the GEIS-33 protocol and treated with MAP (methotrexate, doxorubicin, cisplatin) chemotherapy, surgery, and subsequent adjuvant treatment were included. Nine variants of interest in the VEGFA (rs1570360, rs2010963 and rs699947), FLT1 (VEGFR1; rs7993418, rs9513070 and rs9582036), and KDR (VEGFR2; rs1551641 and rs1870377 and rs2071559) genes were genotyped from peripheral blood samples using TaqMan Assay technology. Genetic data were correlated with relapse-free survival (RFS) and overall survival (OS) considering clinical variables as covariates. Results: The analyses showed nominally significant associations between the FLT1 variants rs7993418 and rs9582036 and survival. Patients carrying the rs7993418(C) allele had worse RFS (p = 0.01) and OS (p = 0.01). Carriers of the minor rs9582036(C) allele also had worse RFS (p = 0.02) and OS (p = 0.03). Additionally, patients harboring the TT genotype of the KDR rs1551641 variant had significantly worse RFS (p = 0.002). These polymorphisms remained statistically significant in the multivariate Cox regression analyses that included surgical margins and pathological response as covariates. Conclusions: Pharmacogenetics may contribute to precision medicine in oncology. Germline polymorphisms in the VEGF pathway may be useful as predictors of survival in high-grade localized osteosarcoma patients treated with chemotherapy, following validation in a large cohort of patients. Current treatment strategies aimed at improving outcomes for osteosarcoma patients may benefit from the identification of new biomarkers, such as these FLT1 rs7993418 and rs9582036 variants. Full article

Kinases, which make up 20% of the druggable genome, are thought to be essential signaling enzymes. Protein phosphorylation is induced by protein kinases. Proliferation, the cell cycle, apoptosis, motility, growth, differentiation, and other biological processes are all regulated by kinases. Their dysregulation disrupts several cellular functions, leading to a variety of illnesses, the most important of which is cancer. As a result, kinases are thought to be crucial targets in a number of malignancies and other diseases. Researchers from all over the world are hard at work developing inhibitors using various chemical structures. The scaffolds of imidazole and benzimidazole provide a versatile structure for a variety of physiologically active substances. Moreover, they serve as specialized scaffolding for the creation of target-specific pharmaceuticals to address various diseases. This article seeks to illustrate the application of imidazole and benzimidazole frameworks in the formulation of inhibitors that target various tyrosine kinases, including fibroblast growth factor receptors (FGFRs), c-Met kinase, epidermal growth factor receptors (EGFRs), vascular endothelial growth factor receptors (VEGFRs), and FMS-like tyrosine kinase 3 (FLT3), from 2020 to the present. The major structure–activity correlations (SARs) of imidazole and benzimidazole derivatives were examined, and, also, a docking study highlighted the varied interactions occurring inside the active site of tyrosine protein kinases. The objective of this effort is to consolidate the fundamental structural information necessary for the synthesis of imidazole- or benzimidazole-based tyrosine kinase inhibitors with enhanced efficacy. Full article

Heartworm disease is caused by Dirofilaria immitis, which mainly affects canids and felids. Adult D. immitis worms are located between the heart’s right ventricle and the pulmonary artery. These parasites produce an inflammatory and hypoxic process in the vascular endothelium. It has been demonstrated that D. immitis excretory/secretory antigens are able to stimulate the angiogenic process as a survival mechanism of D. immitis in the vascular endothelium, stimulating the proangiogenic pathway and related cellular processes. Our goal was to study the role of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and galectin (GAL) (proteins of D. immitis excretory/secretory antigens) plus vascular endothelial growth factor isoform A (VEGF-A) in the angiogenic process and their relationship with three cellular processes (cell proliferation, cell migration, and pseudocapillary formation) in an in vitro model of vascular endothelial cells. Cell viability and cytotoxicity were analyzed by live cell analysis and a commercial kit, respectively. VEGF-A, sVEGFR-2, VEGFR-1/sFlt, soluble endoglin, and membrane endoglin were analyzed by commercial ELISA kits. Cell proliferation, cell migration, and pseudocapillary formation were analyzed by MTT-based assay, the wound healing technique, and counting cell connections and cell clusters, respectively. rDiGAPDH+VEGF-A and rDiGAL+VEGF-A significantly increased the expression of sVEGFR-2, mEndoglin, and VEGF-A compared to cultures treated with only the proteins (rDiGAPDH and rDiGAL), VEGF-A, or unstimulated cultures. In addition, they also produced a significant increase in cell proliferation, cell migration, and pseudocapillary formation. Therefore, these proteins together with VEGF-A can activate the proangiogenic pathway and could be related to D. immitis survival in the circulatory system. Full article

Heartworm disease caused by Dirofilaria immitis is a vector-borne zoonotic disease responsible for the infection of mainly domestic dogs and cats, or these are those for which the most data are known. Humans are an accidental host where a benign, asymptomatic pulmonary nodule may originate. Dirofilaria immitis also harbours the endosymbiont bacteria of the genus Wolbachia, which play a role in moulting, embryogenesis, inflammatory pathology, and immune response. When Wolbachia sp. is released into the bloodstream, endothelial and pulmonary damage is exacerbated, further encouraging thrombus formation and pulmonary hypertension, facilitating congestive heart failure and death of the animal. Previous studies have shown that parasite excretory/secretory products are able to activate the pro-angiogenic pathway (formation of new vessels) to facilitate parasite survival. The aim of this study was to analyse the role of Wolbachia sp. and its relationship with the cellular processes and the angiogenic pathway in a model of human endothelial cells in vitro. The use of recombinant Wolbachia Surface Protein (rWSP) showed that its stimulation exerted an anti-angiogenic effect by detecting an increase in the production of VEGFR-1/sFlt1 and sEndoglin and did not affect the production of VEGFR-2 and mEndoglin (pro-angiogenic molecules). Furthermore, it did not stimulate cell proliferation or migration, although it did negatively stimulate the formation of pseudocapillaries, slowing down this process. These cellular processes are directly related to the angiogenic pathway so, with these results, we can conclude that Wolbachia sp. is related to the stimulation of the anti-angiogenic pathway, not facilitating the survival of D. immitis in vascular endothelium. Full article

Sunitinib has greatly improved the survival of clear cell renal cell carcinoma (ccRCC) patients in recent years. However, 20–30% of treated patients do not respond. To identify miRNAs and genes associated with a response, comparisons were made between biopsies from responder and non-responder ccRCC patients. Using integrated transcriptomic analyses, we identified 37 miRNAs and 60 respective target genes, which were significantly associated with the NF-kappa B, PI3K-Akt and MAPK pathways. We validated expression of the miRNAs (miR-223, miR-155, miR-200b, miR-130b) and target genes (FLT1, PRDM1 and SAV1) in 35 ccRCC patients. High levels of miR-223 and low levels of FLT1, SAV1 and PRDM1 were associated with worse overall survival (OS), and combined miR-223 + SAV1 levels distinguished responders from non-responders (AUC = 0.92). Using immunohistochemical staining of 170 ccRCC patients, VEGFR1 (FLT1) expression was associated with treatment response, histological grade and RECIST (Response Evaluation Criteria in Solid Tumors) score, whereas SAV1 and BLIMP1 (PRDM1) were associated with metachronous metastatic disease. Using in situ hybridisation (ISH) to detect miR-155 we observed higher tumoural cell expression in non-responders, and non-tumoural cell expression with increased histological grade. In summary, our preliminary analysis using integrated miRNA-target gene analyses identified several novel biomarkers in ccRCC patients that surely warrant further investigation. Full article

Hepatocellular carcinoma (HCC) is a highly detrimental cancer type and has limited therapeutic options, posing significant threats to human health. The development of HCC has been associated with a disorder in bile acid (BA) metabolism. In this study, we employed an integrative approach, combining various datasets and omics analyses, to comprehensively characterize the tumor microenvironment in HCC based on genes related to BA metabolism. Our analysis resulted in the classification of HCC samples into four subtypes (C1, C2a, C2b, and C3). Notably, subtype C2a, characterized by the highest bile acid metabolism score (BAMS), exhibited the highest survival probability. This subtype also demonstrated increased immune cell infiltration, lower cell cycle scores, reduced AFP levels, and a lower risk of metastasis compared to subtypes C1 and C3. Subtype C1 displayed poorer survival probability and elevated cell cycle scores. Importantly, the identified subtypes based on BAMS showed potential relevance to the gene expression of drug targets in currently approved drugs and those under clinical research. Genes encoding VEGFR (FLT4 and KDR) and MET were elevated in C2, while genes such as TGFBR1, TGFB1, ADORA3, SRC, BRAF, RET, FLT3, KIT, PDGFRA, and PDGFRB were elevated in C1. Additionally, FGFR2 and FGFR3, along with immune target genes including PDCD1 and CTLA4, were higher in C3. This suggests that subtypes C1, C2, and C3 might represent distinct potential candidates for TGFB1 inhibitors, VEGFR inhibitors, and immune checkpoint blockade treatments, respectively. Significantly, both bulk and single-cell transcriptome analyses unveiled a negative correlation between BA metabolism and cell cycle-related pathways. In vitro experiments further confirmed that the treatment of HCC cell lines with BA receptor agonist ursodeoxycholic acid led to the downregulation of the expression of cell cycle-related genes. Our findings suggest a plausible involvement of BA metabolism in liver carcinogenesis, potentially mediated through the regulation of tumor cell cycles and the immune microenvironment. This preliminary understanding lays the groundwork for future investigations to validate and elucidate the specific mechanisms underlying this potential association. Furthermore, this study provides a novel foundation for future precise molecular typing and the design of systemic clinical trials for HCC therapy. Full article

Vascular endothelial growth factor (VEGF) receptor 3 (VEGFR3), a receptor tyrosine kinase encoded by the FLT4 gene, plays a significant role in the morphogenesis and maintenance of lymphatic vessels. Under both normal and pathologic conditions, VEGF-C and VEGF-D bind VEGFR3 on the surface of lymphatic endothelial cells (LECs) and induce lymphatic proliferation, migration, and survival by activating intracellular PI3K-Akt and MAPK-ERK signaling pathways. Impaired lymphatic function and VEGFR3 signaling has been linked with a myriad of commonly encountered clinical conditions. This review provides a brief overview of intracellular VEGFR3 signaling in LECs and explores examples of dysregulated VEGFR3 signaling in various disease states, including (1) lymphedema, (2) tumor growth and metastasis, (3) obesity and metabolic syndrome, (4) organ transplant rejection, and (5) autoimmune disorders. A more complete understanding of the molecular mechanisms underlying the lymphatic pathology of each disease will allow for the development of novel strategies to treat these chronic and often debilitating illnesses. Full article

Mutations in the transcription factor-coding gene SOX18, the growth factor-coding gene VEGFC and its receptor-coding gene VEGFR3/FLT4 cause primary lymphedema in humans. In mammals, SOX18, together with COUP-TFII/NR2F2, activates the expression of Prox1, a master regulator in lymphatic identity and development. Knockdown studies have also suggested an involvement of Sox18, Coup-tfII/Nr2f2, and Prox1 in zebrafish lymphatic development. Mutants in the corresponding genes initially failed to recapitulate the lymphatic defects observed in morphants. In this paper, we describe a novel zebrafish sox18 mutant allele, sa12315, which behaves as a null. The formation of the lymphatic thoracic duct is affected in sox18 homozygous mutants, but defects are milder in both zygotic and maternal-zygotic sox18 mutants than in sox18 morphants. Remarkably, in sox18 mutants, the expression of the closely related sox7 gene is elevated where lymphatic precursors arise. Sox7 could thus mask the absence of a functional Sox18 protein and account for the mild lymphatic phenotype in sox18 mutants, as shown in mice. Partial knockdown of vegfc exacerbates lymphatic defects in sox18 mutants, making them visible in heterozygotes. Our data thus reinforce the genetic interaction between Sox18 and Vegfc in lymphatic development, previously suggested by knockdown studies, and highlight the ability of Sox7 to compensate for Sox18 lymphatic dysfunction. Full article

Background: FN-1501, a potent inhibitor of receptor FMS-like tyrosine kinase 3 (FLT3) and CDK4/6, KIT, PDGFR, VEGFR2, ALK, and RET tyrosine kinase proteins, has demonstrated significant in vivo activity in various solid tumor and leukemia human xenograft models. Anomalies in FLT3 have an established role as a therapeutic target where the gene has been shown to play a critical role in the growth, differentiation, and survival of various cell types in hematopoietic cancer and have shown promise in various solid tumors. An open-label, Phase I/II study (NCT03690154) was designed to evaluate the safety and PK profile of FN-1501 as monotherapy in patients (pts) with advanced solid tumors and relapsed, refractory (R/R) AML. Methods: Pts received FN-1501 IV three times a week for 2 weeks, followed by 1 week off treatment in continuous 21-day cycles. Dose escalation followed a standard 3 + 3 design. Primary objectives include the determination of the maximum tolerated dose (MTD), safety, and recommended Phase 2 dose (RP2D). Secondary objectives include pharmacokinetics (PK) and preliminary anti-tumor activity. Exploratory objectives include the relationship between pharmacogenetic mutations (e.g., FLT3, TP53, KRAS, NRAS, etc.), safety, and efficacy; as well as an evaluation of the pharmacodynamic effects of treatment with FN-1501. Dose expansion at RP2D further explored the safety and efficacy of FN-1501 in this treatment setting. Results: A total of 48 adult pts with advanced solid tumors (N = 47) and AML (N = 1) were enrolled at doses ranging from 2.5 to 226 mg IV three times a week for two weeks in 21-day cycles (2 weeks on and 1 week off treatment). The median age was 65 years (range 30–92); 57% were female and 43% were male. The median number of prior lines of treatment was 5 (range 1–12). Forty patients evaluable for dose-limiting toxicity (DLT) assessment had a median exposure of 9.5 cycles (range 1–18 cycles). Treatment-related adverse events (TRAEs) were reported for 64% of the pts. The most common treatment-emergent adverse events (TEAEs), defined as those occurring in ≥20% of pts, primarily consisted of reversible Grade 1–2 fatigue (34%), nausea (32%), and diarrhea (26%). The most common Grade ≥3 events occurring in ≥5% of pts consisted of diarrhea and hyponatremia. Dose escalation was discontinued due to DLTs of Grade 3 thrombocytopenia (N = 1) and Grade 3 infusion-related reaction (N = 1) occurring in 2 pts. The maximum tolerated dose (MTD) was determined to be 170 mg. Conclusions: FN-1501 demonstrated reasonable safety, tolerability, and preliminary activity against solid tumors in doses up to 170 mg. Dose escalation was terminated based on 2 DLTs occurring at the 226 mg dose level. Full article

Background and Objectives: Impaired wound healing represents an unsolved medical issue with a high impact on patients’ quality of life and global health care. Even though hypoxia is a significant limiting factor for wound healing, it reveals stimulating effects in gene and protein expression at cellular levels. In particular, hypoxically treated human adipose tissue-derived stem cells (ASCs) have previously been used to stimulate tissue regeneration. Therefore, we hypothesized that they could promote lymphangiogenesis or angiogenesis. Materials and Methods: Dermal regeneration matrices were seeded with human umbilical vein endothelial cells (HUVECs) or human dermal lymphatic endothelial cells (LECs) that were merged with ASCs. Cultures were maintained for 24 h and 7 days under normoxic or hypoxic conditions. Finally, gene and protein expression were measured regarding subtypes of VEGF, corresponding receptors, and intracellular signaling pathways, especially hypoxia-inducible factor-mediated pathways using multiplex-RT-qPCR and ELISA assays. Results: All cell types reacted to hypoxia with an alteration of gene expression. In particular, vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor B (VEGFB), vascular endothelial growth factor C (VEGFC), vascular endothelial growth factor receptor 1 (VEGFR1/FLT1), vascular endothelial growth factor receptor 2 (VEGFR2/KDR), vascular endothelial growth factor receptor 3 (VEGFR3/FLT4), and prospero homeobox 1 (PROX1) were overexpressed significantly depending on upregulation of hypoxia-inducible factor 1 alpha (HIF-1a). Moreover, co-cultures with ASCs showed a more intense change in gene and protein expression profiles and gained enhanced angiogenic and lymphangiogenic potential. In particular, long-term hypoxia led to continuous stimulation of HUVECs by ASCs. Conclusions: Our findings demonstrated the benefit of hypoxic conditioned ASCs in dermal regeneration concerning angiogenesis and lymphangiogenesis. Even a short hypoxic treatment of 24 h led to the stimulation of LECs and HUVECs in an ASC-co-culture. Long-term hypoxia showed a continuous influence on gene expressions. Therefore, this work emphasizes the supporting effects of hypoxia-conditioned-ASC-loaded collagen scaffolds on wound healing in dermal regeneration. Full article

Introduction: Myxofibrosarcoma (MFS) is the most common soft-tissue sarcoma subtype in elderly patients. Local recurrence (LR) remains a major concern as the lack of intraoperative guidance and an infiltrative growth pattern with long, slender tails hamper surgeons’ ability to achieve adequate resection margins for MFS. Fluorescence-guided surgery (FGS) could overcome this concern by delineating tumor tissue during surgery. One of the most important steps to successful FGS is to define a tumor-specific biomarker that is highly overexpressed in tumor tissue while low or absent in adjacent healthy tissue. The aim of this study is to evaluate the expression of eight previously selected promising biomarkers for FGS in MFS tissue samples with adjacent healthy tissue using immunohistochemistry (IHC). Methods: The following eight biomarkers were stained in seventeen paraffin-embedded MFS samples: tumor endothelial marker-1 (TEM-1, also known as endosialin/CD248), vascular endothelial growth factor receptor-1 (VEGFR-1, also known as Flt-1), vascular endothelial growth factor receptor-2 (VEGFR-2, also known as Flk1), vascular endothelial growth factor-A (VEGF-A), epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), platelet derived growth factor receptor-α (PDGFR-α), and cluster of differentiation 40 (CD40, also known as TNFRSF5). A pathologist specializing in sarcoma annotated the margin between the tumor and adjacent healthy tissue in each MFS tissue sample. Subsequently, we used an objective IHC scoring method to assess and compare the difference in staining intensity between the tumor and adjacent healthy tissue, which is crucial for the use of FGS. Results: TEM-1, VEGF-A, and PDGFR-α stained all MFS tumors, while the other biomarkers did not show expression in all MFS tumors. Ultimately, TEM-1 was identified as the most suitable biomarker for FGS in MFS based on higher tumor-to-background (TBR) staining intensity compared to VEGF-A and PDGFR-α, regardless of preoperative therapy. Conclusion: TEM-1-targeted FGS tracers should be further investigated to optimize MFS treatment. Full article

Immunotherapy modulating the tumor microenvironment (TME) immune function has a promising effect on various types of cancers, but it remains as a limited efficacy in colon cancer. Midostaurin (PKC412) has been used in the clinical treatment of fms-like tyrosine kinase 3 (FLT3)-mutant acute myeloid leukemia and has demonstrated immunomodulatory activity. We aimed to evaluate the effect of midostaurin on the modulation of TME and the efficacy of anti-programmed cell death protein 1 (PD-1) against colon cancer. Midostaurin inhibited the growth of murine CT26 and human HCT116 and SW480 cells with multinucleation and micronuclei formation in morphology examination. The cell cycle arrested in the G2/M phase and the formation of the polyploid phase was noted. The formation of cytosolic DNA, including double-strand and single-strand DNA, was increased. Midostaurin increased mRNA expressions of cGAS, IRF3, and IFNAR1 in colorectal adenocarcinoma cells and mouse spleen macrophages. The protein expressions of Trex-1, c-KIT, and Flt3, but not PKCα/β/γ and VEGFR1, were down-regulated in midostaurin-treated colorectal adenocarcinoma cells and macrophages. Trex-1 protein expression was abrogated after FLT3L activation. In vivo, the combination of midostaurin and anti-PD-1 exhibited the greatest growth inhibition on a CT26-implanted tumor without major toxicity. TME analysis demonstrated that midostaurin alone decreased Treg cells and increased neutrophils and inflammatory monocytes. NKG2D⁺ and PD-1 were suppressed and M1 macrophage was increased after combination therapy. When combined with anti-PD-1, STING and INFβ protein expression was elevated in the tumor. The oral administration of midostaurin may have the potential to enhance anti-PD-1 efficacy, accompanied by the modulation of cytosolic DNA-sensing signaling and tumor microenvironment. Full article

A severe form of myopia defined as pathologic/high myopia is the main cause of visual impairment and one of the most frequent causes of blindness worldwide. It is characterized by at least 6 diopters or axial length (AL) of eyeball > 26 mm and choroidal neovascularization (CNV) in 5 to 10% of cases. Ranibizumab is a humanized recombinant monoclonal antibody fragment targeted against human vascular endothelial growth factor A (VEGF-A) used in the treatment of CNV. It acts by preventing VEGF-A from interacting with its receptors (VEGFR-1 and -2) encoded by the FLT1 and KDR genes. Several studies found that the KDR and FLT1 genotypes may represent predictive determinants of efficacy in ranibizumab-treated neovascular age-related macular degeneration (nAMD) patients. We performed a retrospective study to evaluate the association of single nucleotide polymorphisms (SNPs) in VEGFR coding genes with the response rate to ranibizumab in patients with high myopia and CNV. In the association study of genotypes in FLT1 with the response to ranibizumab, we found a significant association between two FLT1 variants (rs9582036, rs7993418) with ranibizumab efficacy at the 12-month follow-up. About the KDR gene, we found that two KDR variants (rs2305948, rs2071559) are associated with best-corrected visual acuity (BCVA) improvement and KDR (rs2239702) is associated with lower rates of BCVA worsening considering a 12-month follow-up period. Full article

Cutaneous squamous cell carcinoma (CSCC) is a common malignant skin cancer with a significant impact on health, and it is important to determine the degree of reliance of CSCC on angiogenesis for growth and metastasis. Major regulators of angiogenesis are the vascular endothelial growth factor (VEGF) family and their associated receptors. Alternative pre-mRNA splicing produces multiple isoforms of VEGF-A and PLGF with distinct biological properties. Several studies highlight the function of VEGF-A in CSCC, but there are no studies of the different isoforms of VEGF-A and PLGF for this neoplasm. We characterized the expression of three isoforms of VEGF-A, two isoforms of PLGF, and their receptors in cat CSCC biopsies compared to normal haired skin (NHS). Although our results revealed no significant changes in transcript levels of panVEGF-A or their isoforms, the mRNA levels of PLGF I and the receptors Flt-1 and KDR were downregulated in CSCC compared to NHS. Differences were observed in ligand:receptor mRNA expression ratio, with the expression of VEGF-A relative to its receptor KDR higher in CSCC, which is consistent with our hypothesis and prior human SCC studies. Immunolocalization in tissue showed increased expression of all measured factors and receptors in tumor cells compared to NHS and surrounding vasculature. We conclude that the factors measured may play a pivotal role in CSCC growth, although further studies are needed to clarify the role of angiogenic factors in feline CSCC. Full article