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  1. Ng KL, Del Vecchio SJ, Samaratunga H, Morais C, Rajandram R, Vesey DA, et al.
    Pathology, 2018 Aug;50(5):504-510.
    PMID: 29970253 DOI: 10.1016/j.pathol.2018.01.007
    One of the challenges in differentiating chromophobe renal cell carcinoma (chRCC) from benign renal oncocytoma (RO) is overlapping morphology between the two subtypes. The aim of this study was to investigate the usefulness of expression of leptin (Ob) and its receptor (ObR) in discriminating chRCC from RO. Sections from paraffin-embedded, formalin-fixed tumour nephrectomy specimens of 45 patients, made up of 30 chRCC (15 eosinophilic variant and 15 non-eosinophilic variant) and 15 RO, were used in this study. Samples (30) of clear cell RCC (ccRCC), the most common histological subtype, were used to verify staining patterns found by others in our cohort of Australasian patients. Matched morphologically normal non-cancer kidney tissues were included for each specimen. Sections were batch-immunostained using antibodies against Ob and ObR. Stained sections were digitally scanned using Aperio ImageScope, and the expression pattern of Ob and ObR was studied. In this cohort, male to female ratio was 2:1; median age was 64 (45-88 years); and median tumour size was 3.8 cm (range 1.2-18 cm). There were 47 (62.7%) T1, seven T2, 20 T3 and one T4 stage RCC. Two patients with ccRCC presented with metastases. Nuclear expression of Ob was significantly higher in RO compared with chRCC. The increased nuclear expression of Ob in RO compared with chRCC may be a useful aid in the difficult histological differentiation of RO from chRCC, especially eosinophilic variants of chRCC.
  2. Morais C, Rajandram R, Blakeney JS, Iyer A, Suen JY, Johnson DW, et al.
    PLoS One, 2021;16(3):e0248983.
    PMID: 33765016 DOI: 10.1371/journal.pone.0248983
    Expression of the protease sensing receptor, protease activated receptor-2 (PAR2), is elevated in a variety of cancers and has been promoted as a potential therapeutic target. With the development of potent antagonists for this receptor, we hypothesised that they could be used to treat renal cell carcinoma (RCC). The expression of PAR2 was, therefore, examined in human RCC tissues and selected RCC cell lines. Histologically confirmed cases of RCC, together with paired non-involved kidney tissue, were used to produce a tissue microarray (TMA) and to extract total tissue RNA. Immunohistochemistry and qPCR were then used to assess PAR2 expression. In culture, RCC cell lines versus primary human kidney tubular epithelial cells (HTEC) were used to assess PAR2 expression by qPCR, immunocytochemistry and an intracellular calcium mobilization assay. The TMA revealed an 85% decrease in PAR2 expression in tumour tissue compared with normal kidney tissue. Likewise, qPCR showed a striking reduction in PAR2 mRNA in RCC compared with normal kidney. All RCC cell lines showed lower levels of PAR2 expression than HTEC. In conclusion, we found that PAR2 was reduced in RCC compared with normal kidney and is unlikely to be a target of interest in the treatment of this type of cancer.
  3. Gobe GC, Ng KL, Small DM, Vesey DA, Johnson DW, Samaratunga H, et al.
    Biochem Biophys Res Commun, 2016 Apr 22;473(1):47-53.
    PMID: 26995091 DOI: 10.1016/j.bbrc.2016.03.048
    Apoptosis repressor with caspase recruitment domain (ARC), an endogenous inhibitor of apoptosis, is upregulated in a number of human cancers, thereby conferring drug resistance and giving a rationale for the inhibition of ARC to overcome drug resistance. Our hypothesis was that ARC would be similarly upregulated and targetable for therapy in renal cell carcinoma (RCC). Expression of ARC was assessed in 85 human RCC samples and paired non-neoplastic kidney by qPCR and immunohistochemistry, as well as in four RCC cell lines by qPCR, Western immunoblot and confocal microscopy. Contrary to expectations, ARC was significantly decreased in the majority of clear cell RCC and in three (ACHN, Caki-1 and 786-0) of the four RCC cell lines compared with the HK-2 non-cancerous human proximal tubular epithelial cell line. Inhibition of ARC with shRNA in the RCC cell line (SN12K1) that had shown increased ARC expression conferred resistance to Sunitinib, and upregulated interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF). We therefore propose that decreased ARC, particularly in clear cell RCC, confers resistance to targeted therapy through restoration of tyrosine kinase-independent alternate angiogenesis pathways. Although the results are contrary to expectations from other cancer studies, they were confirmed here with multiple analytical methods. We believe the highly heterogeneous nature of cancers like RCC predicate that expression patterns of molecules must be interpreted in relation to respective matched non-neoplastic regions. In the current study, this procedure indicated that ARC is decreased in RCC.
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