Genomic imbalances in peripheral blood confirm the diagnosis of myelodysplastic syndrome in a patient presenting with non-immune hemolytic anemia

Myelodysplastic syndrome (MDS) is a clonal stem-cell disorder characterized by dyshematopoiesis. We report a patient who presented with cytopenias and microangiopathic hemolytic anemia. Chromosome microarray analysis (CMA), using single nucleotide polymorphism arrays, on peripheral blood revealed genomic imbalances indicative of MDS, which was confirmed by bone marrow examination. This report highlights the importance of suspecting MDS in patients with cytopenias and microangiopathic hemolytic anemia. CMA of peripheral blood may assist in the preliminary diagnosis of MDS, representing a comparatively less invasive diagnostic procedure and may aid bone marrow evaluation when an aspirate sample is insufficient for conventional cytogenetic analysis

Intratumoral heterogeneity analysis reveals hidden associations between protein expression losses and patient survival in clear cell renal cell carcinoma.

Intratumoral heterogeneity (ITH) is a prominent feature of kidney cancer. It is not known whether it has utility in finding associations between protein expression and clinical parameters. We used ITH that is detected by immunohistochemistry (IHC) to aid the association analysis between the loss of SWI/SNF components and clinical parameters.160 ccRCC tumors (40 per tumor stage) were used to generate tissue microarray (TMA). Four foci from different regions of each tumor were selected. IHC was performed against PBRM1, ARID1A, SETD2, SMARCA4, and SMARCA2. Statistical analyses were performed to correlate biomarker losses with patho-clinical parameters. Categorical variables were compared between groups using Fisher\u27s exact tests. Univariate and multivariable analyses were used to correlate biomarker changes and patient survivals. Multivariable analyses were performed by constructing decision trees using the classification and regression trees (CART) methodology. IHC detected widespread ITH in ccRCC tumors. The statistical analysis of the Truncal loss (root loss) found additional correlations between biomarker losses and tumor stages than the traditional Loss in tumor (total) . Losses of SMARCA4 or SMARCA2 significantly improved prognosis for overall survival (OS). Losses of PBRM1, ARID1A or SETD2 had the opposite effect. Thus Truncal Loss analysis revealed hidden links between protein losses and patient survival in ccRCC

PBRM1 acts as a p53 lysine-acetylation reader to suppress renal tumor growth.

p53 acetylation is indispensable for its transcriptional activity and tumor suppressive function. However, the identity of reader protein(s) for p53 acetylation remains elusive. PBRM1, the second most highly mutated tumor suppressor gene in kidney cancer, encodes PBRM1. Here, we identify PBRM1 as a reader for p53 acetylation on lysine 382 (K382Ac) through its bromodomain 4 (BD4). Notably, mutations on key residues of BD4 disrupt recognition of p53 K382Ac. The mutation in BD4 also reduces p53 binding to promoters of target genes such as CDKN1A (p21). Consequently, the PBRM1 BD4 mutant fails to fully support p53 transcriptional activity and is defective as a tumor suppressor. We also find that expressions of PBRM1 and p21 correlate with each other in human kidney cancer samples. Our findings uncover a tumor suppressive mechanism of PBRM1 in kidney cancer and provide a mechanistic insight into the crosstalk between p53 and SWI/SNF complexes

Expression of Thymidine Phosphorylase in Lymph Nodes Involved with Mycosis Fungoides and Sézary Syndrome

Thymidine phosphorylase may be overexpressed in both neoplastic cells and tumor stromal cells in a variety of malignancies. Our study explores thymidine phosphorylase expression in lymph nodes (LNs) from patients with mycosis fungoides (MF) or Sézary syndrome (SS). In MF/SS, the LNs may have a pathologic diagnosis of either dermatopathic lymphadenopathy (LN-DL) or involvement by MF/SS (LN-MF). We performed immunohistochemical staining on MF/SS lymph nodes using antibodies to thymidine phosphorylase, CD68, CD21, CD3, and CD4. In both LN-DL and benign nodes, thymidine phosphorylase staining was noted only in macrophages, dendritic cells, and endothelial cells. In LN-MF, thymidine phosphorylase expression was also noted in subsets of intermediate to large neoplastic T cells. Concurrent CD68, CD21, CD3, and CD4 staining supported the above observations. Similar results were noted in the skin and in LN-MF with large cell transformation. Other T-cell lymphomas were also examined (total 7 cases); only enteropathy-type T-cell lymphoma (1 case) showed TP positivity in neoplastic T lymphocytes. We demonstrated that thymidine phosphorylase staining is present in neoplastic T cells in mycosis fungoides. The exact mechanism needs further investigation

Multiple tumor suppressors regulate a HIF-dependent negative feedback loop via ISGF3 in human clear cell renal cancer.

Whereas VHL inactivation is a primary event in clear cell renal cell carcinoma (ccRCC), the precise mechanism(s) of how this interacts with the secondary mutations in tumor suppressor genes, including PBRM1, KDM5C/JARID1C, SETD2, and/or BAP1, remains unclear. Gene expression analyses reveal that VHL, PBRM1, or KDM5C share a common regulation of interferon response expression signature. Loss of HIF2α, PBRM1, or KDM5C in VHL-/-cells reduces the expression of interferon stimulated gene factor 3 (ISGF3), a transcription factor that regulates the interferon signature. Moreover, loss of SETD2 or BAP1 also reduces the ISGF3 level. Finally, ISGF3 is strongly tumor-suppressive in a xenograft model as its loss significantly enhances tumor growth. Conversely, reactivation of ISGF3 retards tumor growth by PBRM1-deficient ccRCC cells. Thus after VHL inactivation, HIF induces ISGF3, which is reversed by the loss of secondary tumor suppressors, suggesting that this is a key negative feedback loop in ccRCC. © 2018, Liao et al

Mutational patterns in chemotherapy resistant muscle-invasive bladder cancer

Despite continued widespread use, the genomic effects of cisplatin-based chemotherapy and implications for subsequent treatment are incompletely characterized. Here, we analyze whole exome sequencing of matched pre- and post-neoadjuvant cisplatin-based chemotherapy primary bladder tumor samples from 30 muscle-invasive bladder cancer patients. We observe no overall increase in tumor mutational burden post-chemotherapy, though a significant proportion of subclonal mutations are unique to the matched pre- or post-treatment tumor, suggesting chemotherapy-induced and/or spatial heterogeneity. We subsequently identify and validate a novel mutational signature in post-treatment tumors consistent with known characteristics of cisplatin damage and repair. We find that post-treatment tumor heterogeneity predicts worse overall survival, and further observe alterations in cell-cycle and immune checkpoint regulation genes in post-treatment tumors. These results provide insight into the clinical and genomic dynamics of tumor evolution with cisplatin-based chemotherapy, suggest mechanisms of clinical resistance, and inform development of clinically relevant biomarkers and trials of combination therapies

Case report: reinitiating pembrolizumab treatment after small bowel perforation

Abstract Background Immune checkpoint inhibitors (ICIs) have emerged as paradigm shifting treatment options for a number of cancers. Six antibodies targeting the immune checkpoint proteins programmed cell death 1 (PD-1), programmed cell death 1 ligand 1 (PD-L1) or cytotoxic T-lymphocyte associated protein 4 (CTLA4) have been approved. In some cases, response rates have been impressive, but not uniformly so and not consistently; similarly, toxicity to this class of therapeutic is often unpredictable and can be life threatening. Predicting treatment response and toxicity are two main obstacles to truly individualize treatment with ICIs. One of the most severe and life-threatening adverse events is colitis induced colonic perforation, estimated to occur in 1.0 to 1.5% of patients treated with ICIs. An important question to address is, under what circumstances is it appropriate to reinitiate ICI treatment post-bowel perforation? Case presentation The patient is a 62-year-old woman, who presented with stage IV lung cancer. Immunohistochemical staining indicated that 80% of the patient’s tumor cells expressed PD-L1. The patient was started on a three-week cycle of pembrolizumab. Subsequent reducing in tumor burden was observed within ten weeks. Initially, pembrolizumab was tolerated fairly well, with the exception of immunotherapy related hypothyroidism. However, the patient experienced a second, more serious immune-related adverse event (irAE), in the form of enteritis, which led to small bowel perforation and necessitated exploratory laparotomy. The concerning part of the small bowel was resected, and a primary anastomosis was created. Based on the pathological and surgical findings, the patient was diagnosed with pembrolizumab-associated small bowel perforation. The patient recovered well from surgery and, considering the patient’s remarkable response to treatment, a collective decision was made to reinitiate pembrolizumab on post-operative day twenty-eight. The patient is continuing her immunotherapy with ongoing partial response and is able to continue her full-time job. Conclusions This case report highlights the challenges of identifying patients likely to respond to ICIs and those that are likely to experience irAEs and it discusses the impressive work that has been done to start to address these challenges. Lastly, the topic of reinitiating pembrolizumab treatment even after colonic perforation is discussed