Hepatocellular carcinoma in Peru: A molecular description of an unconventional clinical presentation

INTRODUCTION AND AIM

Hepatocellular carcinoma (HCC) is the third most frequent cancer of digestive tract tumors in Peru, with a high mortality rate of 17.7 per 100,000 inhabitants. A significant number of HCC cases in Peru do not follow the classic clinical epidemiology of the disease described in other parts of the world. Those patients present with a distinct transcriptome profile and a singular tumor process, suggesting a particular type of hepatocarcinogenesis in a portion of the Peruvian population. Our aim was to understand the clinical and biologic involvement of the epigenetic profile (methylation) and gene expression (transcriptome) of HCC in Peruvian patients.

METHODS

HCC and liver transcriptome and DNA methylation profiles were evaluated in 74 Peruvian patients.

RESULTS

When grouped by age, there was greater DNA methylation in younger patients with HCC but no differences with respect to the transcriptomic profile. A high prevalence of the hepatitis B virus (HBV) (>90%) was also observed in the younger patients with HCC. Enrichment analyses in both molecular profiles pinpointed PRC2 as an important molecular effector of that liver tumor process in Peruvian patients.

CONCLUSION

HCC in Peruvian patients has a unique molecular profile, associated with the presence of HBV, as well as overall DNA hypermethylation related to undifferentiated liver cells or cellular reprogramming.

Single-cell spatial explorer: easy exploration of spatial and multimodal transcriptomics

BACKGROUND

The development of single-cell technologies yields large datasets of information as diverse and multimodal as transcriptomes, immunophenotypes, and spatial position from tissue sections in the so-called 'spatial transcriptomics'. Currently however, user-friendly, powerful, and free algorithmic tools for straightforward analysis of spatial transcriptomic datasets are scarce.

RESULTS

Here, we introduce Single-Cell Spatial Explorer, an open-source software for multimodal exploration of spatial transcriptomics, examplified with 9 human and murine tissues datasets from 4 different technologies.

CONCLUSIONS

Single-Cell Spatial Explorer is a very powerful, versatile, and interoperable tool for spatial transcriptomics analysis.

Exposure assessment of 170 pesticide ingredients and derivative metabolites in people from the Central Andes of Peru

The Central Andes of Peru are a region of great concern regarding pesticide risk to the health of local communities. Therefore, we conducted an observational study to assess the level of pesticide contamination among Andean people. Analytical chemistry methods were used to measure the concentrations of 170 pesticide-related compounds in hair samples from 50 adult Andean subjects living in rural and urban areas. As part of the study, a questionnaire was administered to the subjects to collect information regarding factors that increase the risk of pesticide exposure. Our results indicate that Andean people are strongly exposed to agrochemicals, being contaminated with a wide array of pesticide-related compounds at high concentration levels. Multivariate analyses and geostatistical modeling identified sociodemographic factors associated with rurality and food origin that increase pesticide exposure risk. The present study represents the first comprehensive investigation of pesticide-related compounds detected in body samples collected from people living in the Central Andes of Peru. Our findings pinpoint an alarming environmental situation that threatens human health in the region and provide a rationale for improving public policies to protect local communities.

Abstract 2770: Microbiota, mutational landscape and tumor sidedness of colorrectal cancer

Background: Colorectal cancer (CRC) is one of the most common cancers in the world, and it is one of the leading causes of cancer-related death. New biomarker candidates have emerged as an important prognostic and predictive factor and genetic profile approach has been used in the choice of targeted therapies and in the prediction of drug response. The aim of this study was performed a comprehensive genomic profile and intestinal microbiota characterization in peruvian CRC patients to define biomarkers for decision making.

Methods: Patients with CRC diagnosed in 2019 and treated at INEN were included. Tumor samples were collected to assessed the presence of high-risk human papillomavirus (HPV) and Epstein-Bar virus (EBV) by qPCR, microsatellite instability (MSI) by IHC and somatic genomic alterations by next generation sequencing (NGS) using Ampliseq FOCUS panel (Illumina). Fecal samples were self-collected to performed V3-V4 region 16S ribosomal RNA metagenomics sequencing (Illumina).

Results: The study included 40 CRC patients with a mean age at diagnosis of 56 (28-90) years, 59.2% were men. Clinical stages were distributed, in I-II (16.5%), III (37.5%), IV (27.5%). The remaining 12.5% had an unknown tumor stage at diagnosis. The 62.5% of patients underwent tumor surgical treatment. Most tumors (85%) were adenocarcinoma NOS and moderately differentiated (65%). Tumor location was rectum (RC; 27.5%), right side colon (RCC; 42.5%) and left side colon (LCC; 30%). Chemotherapy was administered in 30%. The median follow-up period was 11.1 months (2-28). MSI was high (20%), low (10%) and stable (70%). HPV and EBV DNA was detected in 42.5% and 82.5% of CRC patients respectively. The prevalence of genomic alterations was 77.5%. KRAS alterations were found in 47.5% patients. BRAF (5%), NRAS (2.5%), PIK3CA (12.5%), APC (2.5%), and AKT1 (2.5%). All PIK3CA and BRAF variants were found in RCC. No variants were found in the NTRK or HER2 amplifications. Patients with BRAF variant had a median survival rate only 5 months (3-7). MSI-high/low was present only in colon, showing dominance on the RCC (66.7%). Verrucomicrobia, Staphylococcus, Peptostreptococcus and Clostridium were present in both RCC and LCC. Clostridium and Peptostreptococcus were highly enriched in the LCC. Campylobacter and Spirochaeta were found only in the LCC. Surprisingly, Fusobacterium was found in RCC except one patient in LCC. Bifidobacterium and Acinetobacter were present only in LCC and RC. Elusimicrobia, Shigella and WPS-2 were found only in RC.

Conclusion: The current pressure to select the best treatment has generated intense interest in the evaluation of CRC molecular alterations characteristic to define prognostic and predictive biomarkers of disease and treatment in our population. This study constitutes the first integrative biomarkers research in peruvian CRC patients showing a diferent molecular signatures between RCC, LCC and RC patients.

Citation Format: Bruno A. Muñante Luna, Jhoysi Casas Goñas, Manuel Chumpitaz, Juan Pablo Cerapio, Marcos Santos Chavez, Mariela Huerta-Rosario, Franco Doimi Garcia, Juan F. Olivos Gonzales, Claudia Jiménez Orosco, Daniel Valdivia Leonardo, Luis F. Barreda Bolaños, Silvia Neciosup Delgado, Victor Castro Oliden, Paola Montenegro Beltran, Luis Mas Lopez, Eduardo Payet Meza, Carolina Belmar-López. Microbiota, mutational landscape and tumor sidedness of colorrectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2770.

A preoperative nomogram for predicting long-term survival after resection of large hepatocellular carcinoma (>10 cm)

BACKGROUND

It has previously been demonstrated that a fraction of patients with hepatocellular carcinoma (HCC) > 10 cm can benefit from liver resection. However, there is still a lack of effective decision-making tools to inform intervention in these patients.

METHODS

We analysed a comprehensive set of clinical data from 234 patients who underwent liver resection for HCC >10 cm at the National Cancer Institute of Peru between 1990 and 2015, monitored their survival, and constructed a nomogram to predict the surgical outcome based on preoperative variables.

RESULTS

We identified cirrhosis, multifocality, macroscopic vascular invasion, and spontaneous tumour rupture as independent predictors of survival and integrated them into a nomogram model. The nomogram's ability to forecast survival at 1, 3, and 5 years was subsequently confirmed with high concordance using an internal validation. Through applying this nomogram, we stratified three groups of patients with different survival probabilities.

CONCLUSION

We constructed a preoperative nomogram to predict long-term survival in patients with HCC >10 cm. This nomogram is useful in determining whether a patient with large HCC might truly benefit from liver resection, which is paramount in low- and middle-income countries where HCC is often diagnosed at advanced stages.

Global DNA hypermethylation pattern and unique gene expression signature in liver cancer from patients with Indigenous American ancestry

Hepatocellular carcinoma (HCC) usually afflicts individuals in their maturity after a protracted liver disease. Contrasting with this pattern, the age structure of HCC in Andean people displays a bimodal distribution with half of the patients developing HCC in adolescence and early adulthood. To deepen our understanding of the molecular determinants of the disease in this population, we conducted an integrative analysis of gene expression and DNA methylation in HCC developed by 74 Peruvian patients, including 39 adolescents and young adults. While genome-wide hypomethylation is considered as a paradigm in human HCCs, our analysis revealed that Peruvian tumors are associated with a global DNA hypermethylation. Moreover, pathway enrichment analysis of transcriptome data characterized an original combination of signatures. Peruvian HCC forgoes canonical activations of IGF2, Notch, Ras/MAPK, and TGF-β signals to depend instead on Hippo/YAP1, MYC, and Wnt/β-catenin pathways. These signatures delineate a homogeneous subtype of liver tumors at the interface of the proliferative and non-proliferative classes of HCCs. Remarkably, the development of this HCC subtype occurs in patients with one of the four Native American mitochondrial haplogroups A-D. Finally, integrative characterization revealed that Peruvian HCC is apparently controlled by the PRC2 complex that mediates cell reprogramming with massive DNA methylation modulating gene expression and pinpointed retinoid signaling as a potential target for epigenetic therapy.

Natural Occurrence of Mycotoxin-Producing Fusaria in Market-Bought Peruvian Cereals: A Food Safety Threat for Andean Populations

Consumption of cereals contaminated by mycotoxins poses health risks. For instance, Fumonisins B, mainly produced by Fusarium verticillioides and Fusariumproliferatum, and the type B trichothecene deoxynivalenol, typically produced by Fusarium graminearum, are highly prevalent on cereal grains that are staples of many cultural diets and known to represent a toxic risk hazard. In Peru, corn and other cereals are frequently consumed on a daily basis under various forms, the majority of food grains being sold through traditional markets for direct consumption. Here, we surveyed mycotoxin contents of market-bought grain samples in order to assess the threat these mycotoxins might represent to Peruvian population, with a focus on corn. We found that nearly one sample of Peruvian corn out of six was contaminated with very high levels of Fumonisins, levels mostly ascribed to the presence of F. verticillioides. Extensive profiling of Peruvian corn kernels for fungal contaminants could provide elements to refine the potential risk associated with Fusarium toxins and help define adapted food safety standards.