The role of cytoreductive surgery and HIPEC for the treatment of primary and secondary peritoneal malignancies-experience from a tertiary care center in Germany.

PURPOSE: Peritoneal surface malignancies (PSM) are commonly known to have a dismal prognosis. Over the past decades, novel techniques such as cytoreductive surgery (CRS), hyperthermic intraperitoneal chemotherapy (HIPEC), and pressurized intraperitoneal aerosol chemotherapy (PIPAC) have been introduced for the treatment of PSM which could improve the overall survival and quality of life of patients with PSM. The decision to proceed with CRS and HIPEC is often challenging due the complexity of the disease, the extent of the procedure, associated side effects, and potential risks. Here, we present our experience with CRS and HIPEC to add to the ongoing discussion about eligibility criteria, technical approach, and expected outcomes and contribute to the evolution of this powerful and promising tool in the multidisciplinary treatment of patients with primary and secondary PSM. METHODS: A single-center retrospective chart review was conducted and included a total of 40 patients treated with CRS and HIPEC from April 2020 to September 2022 at the University Hospital Münster Department of Surgery. All patients had histologically confirmed primary or secondary peritoneal malignancies of various primary origins. RESULTS: Our study included 22 patients with peritoneal metastases from gastric cancer (55%), 8 with pseudomyxoma peritonei (20%), 4 with mesothelioma of the peritoneum (10%), and 6 patients with PSM originating from other primary tumor locations. Median PCI at time of cytoreduction was 4 (0-25). Completeness of cytoreduction score was 0 in 37 patients (92.5%), 1 in two patients (5%), and 2 in one patient (2.5%). Median overall survival across all patients was 3.69 years. CONCLUSION: Complete cytoreduction during CRS and HIPEC can be achieved for patients with low PCI, for patients with high PCI in low-grade malignancies, and even for patients with initially high PCI in high-grade malignancies following a significant reduction of cancer burden due to extensive preoperative treatment with PIPAC and systemic chemotherapy.

The Potential of Aptamer-Mediated Liquid Biopsy for Early Detection of Cancer.

The early detection of cancer favors a greater chance of curative treatment and long-term survival. Exciting new technologies have been developed that can help to catch the disease early. Liquid biopsy is a promising non-invasive tool to detect cancer, even at an early stage, as well as to continuously monitor disease progression and treatment efficacy. Various methods have been implemented to isolate and purify bio-analytes in liquid biopsy specimens. Aptamers are short oligonucleotides consisting of either DNA or RNA that are capable of binding to target molecules with high specificity. Due to their unique properties, they are considered promising recognition ligands for the early detection of cancer by liquid biopsy. A variety of circulating targets have been isolated with high affinity and specificity by facile modification and affinity regulation of the aptamers. In this review, we discuss recent progress in aptamer-mediated liquid biopsy for cancer detection, its associated challenges, and its future potential for clinical applications.

MacroH2A histone variants limit chromatin plasticity through two distinct mechanisms.

MacroH2A histone variants suppress tumor progression and act as epigenetic barriers to induced pluripotency. How they impart their influence on chromatin plasticity is not well understood. Here, we analyze how the different domains of macroH2A proteins contribute to chromatin structure and dynamics. By solving the crystal structure of the macrodomain of human macroH2A2 at 1.7 Å, we find that its putative binding pocket exhibits marked structural differences compared with the macroH2A1.1 isoform, rendering macroH2A2 unable to bind ADP-ribose. Quantitative binding assays show that this specificity is conserved among vertebrate macroH2A isoforms. We further find that macroH2A histones reduce the transient, PARP1-dependent chromatin relaxation that occurs in living cells upon DNA damage through two distinct mechanisms. First, macroH2A1.1 mediates an isoform-specific effect through its ability to suppress PARP1 activity. Second, the unstructured linker region exerts an additional repressive effect that is common to all macroH2A proteins. In the absence of DNA damage, the macroH2A linker is also sufficient for rescuing heterochromatin architecture in cells deficient for macroH2A.

High Expression of miR-34a Associated with Less Aggressive Cancer Biology but Not with Survival in Breast Cancer.

Most breast cancer (BC) patients succumb to metastatic disease. MiR-34a is a well-known tumor suppressive microRNA which exerts its anti-cancer functions by playing a role in p53, apoptosis induction, and epithelial-mesenchymal transition (EMT) suppression. Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and The Cancer Genome Atlas (TCGA) cohorts were used to test our hypothesis that miR-34a high BCs translate to less aggressive cancer biology and better survival in large cohorts. There was no association between miR-34a expression levels and clinicopathological features of BC patients except for HER2 positivity. MiR-34a high expressing tumors were associated with lower Nottingham pathological grades and lower MKI67 expression. In agreement, high miR-34a tumors demonstrated lower GSVA scores of cell cycle and cell proliferation-related gene sets. High miR-34a tumors enriched the p53 pathway and apoptosis gene sets. Unexpectedly, high miR-34a tumors also associated with elevated EMT pathway score and ZEB1 and two expressions. MiR-34a expression did not associate with any distant metastasis. Further, high miR-34a tumors did not associate with better survival compared with miR-34a low tumors. In conclusion, the clinical relevance of miR-34a high expressing tumors was associated with suppressed cell proliferation, enhanced p53 pathway and apoptosis, but enhanced EMT and these findings did not reflect better survival outcomes in large BC patient cohorts.

Expression of MicroRNA-9 is Associated With Overall Survival in Breast Cancer Patients.

BACKGROUND: MicroRNA-9 (miR-9) was found to play an important role in a variety of different cancers and can adopt either tumor suppressor or oncogenic activity. Most studies have suggested an oncogenic role in breast cancer. We were interested in the relationship of miR-9 expression and survival in breast cancer and hypothesized that high expression of miR-9 was associated with worse prognosis in breast cancer patients. MATERIALS AND METHODS: We utilized The Cancer Genome Atlas containing genetic and molecular data, clinical profiles, and survival information for 985 breast cancers. Survival analysis was performed comparing a group with low expression of miR-9 to a group with high expression. Expression of miR-9 was compared based on clinicopathological parameters. Gene set enrichment analysis was performed between the miR-9 high- and low-expression groups within the estrogen receptor (ER)-positive cohort. RESULTS: Low expression of miR-9 associated significantly with improved overall survival (OS) (P = 0.003). There was no significant difference in miR-9 expression with regard to disease-free survival. Smaller and early-stage tumors were associated with lower miR-9 expression. ER-positive breast cancers had lower levels of miR-9 than ER-negative breast cancers (P < 0.001), and within the ER-positive group, miR-9 expression was significantly associated with OS (P = 0.02). Gene set enrichment analysis showed enrichment of estrogen response genes in the miR-9 low-expression group. CONCLUSIONS: Low miR-9 expression appeared to have a protective effect and was associated with improved OS, smaller tumors, earlier stage, and ER-positive cancers due to enrichment of estrogen response genes.

Modified scoring system for the quantitative assessment of histological regression in peritoneal carcinomatosis after pressurized intraperitoneal aerosol chemotherapy: A pilot study.

Peritoneal carcinomatosis is one of the leading causes of death in patients with gastrointestinal cancer. Newer locoregional treatment concepts include pressurized intraperitoneal aerosol chemotherapy (PIPAC), the regional application of pressurized chemotherapeutic agents to the abdominal cavity, which is usually performed every 4 to 8 weeks. One of the main challenges of PIPAC therapy remains the objective assessment of treatment response. The present study describes a new scoring system to histologically assess the regression of peritoneal cancer following PIPAC therapy, quantitative assessment of histological regression in peritoneal carcinomatosis (QARP). Peritoneal biopsies from 27 patients with peritoneal metastases undergoing PIPAC were obtained and processed in a standardized fashion. Biopsies were scored according to the QARP grading system. The five-tiered system was graded as follows, Grade 0, no residual tumor cells with regressive changes present; grade 1, 1-25% viable tumor cells per tumor focus with regressive changes present; grade 2, 26-50% viable tumor cells per tumor focus with regressive changes present; grade 3, 51-75% viable tumor cells per tumor focus with few regressive changes; grade 4, >75% viable tumor cells per tumor focus with minimal or no regressive changes. Based on the new grading system, the study cohort was divided into QARP responders and QARP non-responders following PIPAC treatment. Higher QARP scores were significantly correlated with higher PCI scores (r=0.32; P=0.007). However, no difference in overall survival was detected between QARP responders and QARP non-responders. Further studies are required to ascertain the reproducibility and prognostic significance of QARP.

Differential regulation and predictive potential of MacroH2A1 isoforms in colon cancer.

Histone variant macroH2A1 has two splice isoforms, macroH2A1.1 and macroH2A1.2, with tissue- and cell-specific expression patterns. Although macroH2A1.1 is mainly found in differentiated, nonproliferative tissues, macroH2A1.2 is more generally expressed, including in tissues with ongoing cell proliferation. Consistently, studies in breast and lung cancer have demonstrated a strong correlation between macroH2A1.1 levels and proliferation, which is not the case for macroH2A1.2. This is the first study to assess the differential regulation and predictive potential of macroH2A1 isoforms in colon cancer. We found that macroH2A1.1 mRNA was down-regulated in primary colorectal cancer samples compared to matched normal colon tissue, whereas macroH2A1.2 was up-regulated. At the protein level, down-regulation of macroH2A1.1 correlated significantly with patient outcome (P = 0.0012), and loss of macroH2A1.1 was associated with a worse outcome. Over the course of Caco-2 cell differentiation, macroH2A1.1 was up-regulated at both the RNA and protein levels, whereas macroH2A1.2 was slightly down-regulated at the RNA level and stable at the protein level. These changes were accompanied by an antiproliferative phenotype exhibiting features of cellular senescence. Loss of macroH2A1.1 in vitro was characterized by a phenotype associated with cell growth and metastasis. These data demonstrate that macroH2A1 isoforms are differentially regulated in colon cancer, reflecting the degree of cellular differentiation. Notably, macroH2A1.1 expression predicts survival in colon cancer, thus identifying macroH2A1.1 as a novel colon cancer biomarker.

Loss of histone variant macroH2A2 expression associates with progression of anal neoplasm.

AIMS: The macroH2A histone variants are epigenetic marks for inactivated chromatin. In this study, we examined the expression of macroH2A2 in anal neoplasm from anal intraepithelial neoplasia (AIN) to anal squamous cell carcinoma (SCC). METHODS: AIN and anal SCC samples were analysed for macroH2A2 expression, HIV and human papilloma virus (HPV). The association of macroH2A2 expression with clinical grade, disease recurrence, overall survival and viral involvement was determined. RESULTS: macroH2A2 was expressed in normal squamous tissue and lower grade AIN (I and II). Expression was lost in 38% of high-grade AIN (III) and 71% of anal SCC (p=0.002). Patients with AIN with macroH2A2-negative lesions showed earlier recurrence than those with macroH2A2-positive neoplasm (p=0.017). With anal SCC, macroH2A2 loss was more prevalent in the HPV-negative tumours. CONCLUSIONS: Loss of histone variant macroH2A2 expression is associated with the progression of anal neoplasm and can be used as a prognostic biomarker for high-grade AIN and SCC.

Expression of an Oncogenic BARD1 Splice Variant Impairs Homologous Recombination and Predicts Response to PARP-1 Inhibitor Therapy in Colon Cancer.

BRCA1-associated RING domain protein 1 (BARD1) stabilizes BRCA1 protein by forming a heterodimeric RING-RING complex, and impacts function of BRCA1, including homologous recombination (HR) repair. Although colon cancer cells usually express wild type BRCA1, presence of an oncogenic BARD1 splice variant (SV) in select cancers may render BRCA1 dysfunctional and allow cells to become sensitive to HR targeting therapies. We previously reported association of loss of full-length (FL) BARD1 with poor prognosis in colon cancer as well as expression of various BARD1 SVs with unknown function. Here we show that loss of BARD1 function through the expression of a BARD1 SV, BARD1ß, results in a more malignant phenotype with decreased RAD51 foci formation, reduced BRCA1 E3 ubiquitin ligase activity, and decreased nuclear BRCA1 protein localization. BARD1ß sensitizes colon cancer cells to poly ADP ribose polymerase 1 (PARP-1) inhibition even in a FL BRCA1 background. These results suggest that expression of BARD1ß may serve as a future biomarker to assess suitability of colon cancers for HR targeting with PARP-1 inhibitors in treatment of advanced colon cancer.

Effects of activin and TGFß on p21 in colon cancer.

Activin and TGFß share SMAD signaling and colon cancers can inactivate either pathway alone or simultaneously. The differential effects of activin and TGFß signaling in colon cancer have not been previously dissected. A key downstream target of TGFß signaling is the cdk2 inhibitor p21 (p21(cip1/waf1)). Here, we evaluate activin-specific effects on p21 regulation and resulting functions. We find that TGFß is a more potent inducer of growth suppression, while activin is a more potent inducer of apoptosis. Further, growth suppression and apoptosis by both ligands are dependent on SMAD4. However, activin downregulates p21 protein in a SMAD4-independent fashion in conjunction with increased ubiquitination and proteasomal degradation to enhance migration, while TGFß upregulates p21 in a SMAD4-dependent fashion to affect growth arrest. Activin-induced growth suppression and cell death are dependent on p21, while activin-induced migration is counteracted by p21. Further, primary colon cancers show differential p21 expression consistent with their ACVR2/TGFBR2 receptor status. In summary, we report p21 as a differentially affected activin/TGFß target and mediator of ligand-specific functions in colon cancer, which may be exploited for future risk stratification and therapeutic intervention.

BARD1 expression predicts outcome in colon cancer.

PURPOSE: BARD1 is a BRCA1-binding partner with tumor suppressive properties. Aberrant splice variants of BARD1 have been detected in various cancers, and it has been postulated that the presence of some splice variants is cancer specific. This is the first study assessing BARD1 expression patterns and correlation with clinical outcome in colon cancer. EXPERIMENTAL DESIGN: We analyzed colon cancer samples for the occurrence of BARD1 splice variants, characterized novel BARD1 splice variants, and quantified the mRNA expression levels of these isoforms in primary colon cancers and their corresponding normal tissue. We tested the correlation of full-length BARD1 protein expression and clinical outcome in primary colon cancer samples. RESULTS: In addition to the full-length BARD1 mRNA, we now find 19 distinct BARD1 splice variants in colon cancer. Contrary to previous assumptions, these splice variants also occur in the adjacent normal colon tissue. Although BARD1 splice variants account for a considerable amount of BARD1 mRNA in both cancer and normal colon samples, distinct variants show a cancer-specific regulation pattern. Consistent with its role as tumor suppressor, we further find that the expression of the full-length BARD1 protein predicts outcome in colon cancer and that loss of full-length BARD1 protein is associated with a poor prognosis (P = 0.0002). CONCLUSION: Taken together, this is the first report to suggest that BARD1 regulation is an important pathway in colon cancer and that the BARD1 full-length protein may be a useful marker to improve risk stratification in colon cancer patients.

Activin signaling in microsatellite stable colon cancers is disrupted by a combination of genetic and epigenetic mechanisms.

BACKGROUND: Activin receptor 2 (ACVR2) is commonly mutated in microsatellite unstable (MSI) colon cancers, leading to protein loss, signaling disruption, and larger tumors. Here, we examined activin signaling disruption in microsatellite stable (MSS) colon cancers. METHODS: Fifty-one population-based MSS colon cancers were assessed for ACVR1, ACVR2 and pSMAD2 protein. Consensus mutation-prone portions of ACVR2 were sequenced in primary cancers and all exons in colon cancer cell lines. Loss of heterozygosity (LOH) was evaluated for ACVR2 and ACVR1, and ACVR2 promoter methylation by methylation-specific PCR and bisulfite sequencing and chromosomal instability (CIN) phenotype via fluorescent LOH analysis of 3 duplicate markers. ACVR2 promoter methylation and ACVR2 expression were assessed in colon cancer cell lines via qPCR and IP-Western blots. Re-expression of ACVR2 after demethylation with 5-aza-2'-deoxycytidine (5-Aza) was determined. An additional 26 MSS colon cancers were assessed for ACVR2 loss and its mechanism, and ACVR2 loss in all tested cancers correlated with clinicopathological criteria. RESULTS: Of 51 MSS colon tumors, 7 (14%) lost ACVR2, 2 (4%) ACVR1, and 5 (10%) pSMAD2 expression. No somatic ACVR2 mutations were detected. Loss of ACVR2 expression was associated with LOH at ACVR2 (p<0.001) and ACVR2 promoter hypermethylation (p<0.05). ACVR2 LOH, but not promoter hypermethylation, correlated with CIN status. In colon cancer cell lines with fully methylated ACVR2 promoter, loss of ACVR2 mRNA and protein expression was restored with 5-Aza treatment. Loss of ACVR2 was associated with an increase in primary colon cancer volume (p<0.05). CONCLUSIONS: Only a small percentage of MSS colon cancers lose expression of activin signaling members. ACVR2 loss occurs through LOH and ACVR2 promoter hypermethylation, revealing distinct mechanisms for ACVR2 inactivation in both MSI and MSS subtypes of colon cancer.