Aims: Papillary renal neoplasm with reverse polarity (PRNRP) is a newly documented rare tumour type. Its molecular pathological features have thus far been very little studied. Methods and results: There were 13 PRNRP cases including 3 The Cancer Genome Atlas (TCGA) cases and our 10 cases in this study. The 3 TCGA cases were found by a combined analysis of GATA3 mRNA expression levels and digital slides from the TCGA papillary renal cell carcinoma project. KRAS codon 12 mutations were identified in the three PRNRPs from TCGA. Of our 10 PRNRP cases, the mutations were also discovered using Sanger sequencing in seven (77.8%) of nine cases with available DNA, where KRAS p.G12V (n = 3), p.G12D (n = 2), p.G12R (n = 1) and p.G12C (n = 1) alterations were found. PRNRP shared similar gene expression profiles with renal distal tubules via an interprofile correlation analysis. Gene set enrichment analysis revealed that genes involved in 'KEGG aldosterone regulated sodium reabsorption' or 'hallmark apical surface' were enriched in PRNRP. Moreover, polarised immunostaining patterns for L1CAM and EMA in the distal tubule were maintained in PRNRP. Conclusions: These results imply that the tumour potentially originates from the distal tubule, especially from the cortical collecting duct, and probably retains its cell polarity, except for nuclear inversion. We therefore propose that oncocytic papillary renal neoplasm with inverted nuclei (OPR-NIN) is a better name for this tumour type. OPRNIN is a kidney site-specific KRAS mutation neoplasm different from conventional papillary renal cell carcinoma.

Primary hyperparathyroidism (PHPT) is mainly caused by parathyroid adenoma, which produces excess parathyroid hormones. Its pathogenic mechanisms have not yet been fully understood. To investigate the mechanism in the pathogenesis of PHPT, the transcriptome and genome-wide DNA methylation profiles of parathyroid adenoma were analyzed. The candidate genes that may be involved in the PHPT were verified via qRT-PCR, immunohistochemistry, western blot, and methylation-specific PCR. A total of 1650 differentially expressed genes and 2373 differentially methylated regions were identified. After the integration of its transcriptome and DNA methylation data, IL6, SYP, GNA01, and pro-opiomelanocortin (POMC) were the candidate genes that demonstrated a similar pattern between their mRNA expression and DNA methylation status. Of the 4 candidate genes, POMC, a pro-peptide which is processed to a range of bioactive peptide products like ACTH, was further confirmed to be expressed at low levels at both the mRNA and protein levels, which may be due to POMC promoter hypermethylation. Hypermethylation of the POMC promoter may contribute to its low expression, which may be involved in the pathogenesis of PHPT.

Hepatocellular carcinoma (HCC) is an aggressive liver tumor that occurs due to chronic liver disease, and it has a high mortality rate and limited treatment options. Immune checkpoint inhibitors have been successfully introduced and used in cancer therapy, among which inhibitors of programmed death ligand-1 (PD-L1) and its receptor programmed death-1 (PD-1) are commonly administered for HCC as combination therapy, including combined anti-angiogenic and immunotherapy combination therapy. We report a case of a primary massive HCC patient with portal hepatic vein tumor thrombus who had a good response to atezolizumab in combination with bevacizumab, following progression of disease on combined immunotherapy with pembrolizumab and lenvatinib. This case demonstrates for the first time that an HCC patient who is resistant to anti-PD-1 antibody immunotherapy can benefit from anti-PD-L1 antibody immunotherapy, providing a potentially promising strategy for the treatment of HCC.

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