Spatial Effects of Infiltrating T cells on Neighbouring Cancer Cells and Prognosis in Stage III CRC patients

Colorectal cancer (CRC) is one of the most frequently occurring cancers, but prognostic biomarkers identifying patients at risk of recurrence are still lacking. In this study, we aimed to investigate in more detail the spatial relationship between intratumoural T cells, cancer cells, and cancer cell hallmarks, as prognostic biomarkers in stage III colorectal cancer patients. We conducted multiplexed imaging of 56 protein markers at single cell resolution on resected fixed tissue from stage III CRC patients who received adjuvant 5-fluorouracil-based chemotherapy. Images underwent segmentation for tumour, stroma and immune cells, and cancer cell 'state' protein marker expression was quantified at a cellular level. We developed a Python package for estimation of spatial proximity, nearest neighbour analysis focusing on cancer cell - T cell interactions at single-cell level. In our discovery cohort (MSK), we processed 462 core samples (total number of cells: 1,669,228) from 221 adjuvant 5FU-treated stage III patients. The validation cohort (HV) consisted of 272 samples (total number of cells: 853,398) from 98 stage III CRC patients. While there were trends for an association between percentage of cytotoxic T cells (across the whole cancer core), it did not reach significance (Discovery cohort: p = 0.07, Validation cohort: p = 0.19). We next utilized our region-based nearest neighbourhood approach to determine the spatial relationships between cytotoxic T cells, helper T cells and cancer cell clusters. In the both cohorts, we found that lower distance between cytotoxic T cells, T helper cells and cancer cells was significantly associated with increased disease-free survival. An unsupervised trained model that clustered patients based on the median distance between immune cells and cancer cells, as well as protein expression profiles, successfully classified patients into low-risk and high-risk groups (Discovery cohort: p = 0.01, Validation cohort: p = 0.003).

Identification of unique rectal cancer-specific subtypes

BACKGROUND

Existing colorectal cancer subtyping methods were generated without much consideration of potential differences in expression profiles between colon and rectal tissues. Moreover, locally advanced rectal cancers at resection often have received neoadjuvant chemoradiotherapy which likely has a significant impact on gene expression.

METHODS

We collected mRNA expression profiles for rectal and colon cancer samples (n = 2121). We observed that (i) Consensus Molecular Subtyping (CMS) had a different prognosis in treatment-naïve rectal vs. colon cancers, and (ii) that neoadjuvant chemoradiotherapy exposure produced a strong shift in CMS subtypes in rectal cancers. We therefore clustered 182 untreated rectal cancers to find rectal cancer-specific subtypes (RSSs).

RESULTS

We identified three robust subtypes. We observed that RSS1 had better, and RSS2 had worse disease-free survival. RSS1 showed high expression of MYC target genes and low activity of angiogenesis genes. RSS2 exhibited low regulatory T cell abundance, strong EMT and angiogenesis signalling, and high activation of TGF-β, NF-κB, and TNF-α signalling. RSS3 was characterised by the deactivation of EGFR, MAPK and WNT pathways.

CONCLUSIONS

We conclude that RSS subtyping allows for more accurate prognosis predictions in rectal cancers than CMS subtyping and provides new insight into targetable disease pathways within these subtypes.

Multiplexed Immunofluorescence Imaging Reveals an Immune-Rich Tumor Microenvironment in Mucinous Rectal Cancer Characterized by Increased Lymphocyte Infiltration and Enhanced Programmed Cell Death Protein 1 Expression

BACKGROUND

Mucinous rectal cancer is associated with a higher incidence of microsatellite instability and a poorer response to neoadjuvant chemoradiotherapy compared to other subtypes of rectal adenocarcinoma. Immune checkpoint inhibitors are an emerging family of anticancer therapeutics associated with highly variable outcomes in colorectal cancer. Although the immune landscape of mucinous rectal cancer has not been fully explored, the presence of mucin is thought to act as a barrier preventing immune-cell infiltration.

OBJECTIVE

The aim of this study was to determine the immune properties of mucinous rectal cancer and investigate the degree of lymphocyte infiltration in this cohort.

DESIGN

This is a retrospective cohort study that involved multiplexed immunofluorescence staining of tumor microarrays.

SETTINGS

Samples originated from a single university teaching hospital.

PATIENTS

Our cohort included 15 cases of mucinous and 43 cases of nonmucinous rectal cancer.

MAIN OUTCOME MEASURES

Immune cells were classified and quantified. Immune-cell counts were compared between mucinous and nonmucinous cohorts. Immune marker expression within tumor epithelial tissue was evaluated to determine the degree of lymphocyte infiltration.

RESULTS

Cytotoxic ( p = 0.022) and regulatory T cells ( p = 0.010) were found to be overrepresented in the mucinous cohort compared to the nonmucinous group. Programmed cell death protein 1 expression was also found to be significantly greater in the mucinous group ( p = 0.001). CD3 ( p = 0.001) and CD8 ( p = 0.054) expressions within the tumor epithelium were also higher in the mucinous group, suggesting adequate immune infiltration despite the presence of mucin. In our analysis, microsatellite instability status was not a predictor of immune marker expression.

LIMITATIONS

The relatively small size of the cohort.

CONCLUSIONS

Mucinous rectal cancer is associated with an immune-rich tumor microenvironment, which was not associated with microsatellite instability status. See Video Abstract at http://links.lww.com/DCR/C65 .

IMGENES DE INMUNOFLUORESCENCIA MULTIPLEXADAS REVELAN UN MICROAMBIENTE TUMORAL RICO EN INMUNIDAD EN EL CNCER RECTAL MUCINOSO CARACTERIZADO POR UNA MAYOR INFILTRACIN DE LINFOCITOS Y UNA EXPRESIN MEJORADA DE PD

ANTECEDENTES:El cáncer rectal mucinoso se asocia con una mayor incidencia de inestabilidad de microsatélites y una peor respuesta a la quimiorradioterapia neoadyuvante en comparación con otros subtipos de adenocarcinoma rectal. Los inhibidores de puntos de control inmunitarios son una familia emergente de tratamientos contra el cáncer asociados con resultados muy variables en el cáncer colorrectal. Aunque el panorama inmunitario del cáncer rectal mucinoso no se ha explorado completamente, se cree que la presencia de mucina actúa como una barrera que previene la infiltración de células inmunitarias.OBJETIVO:El objetivo de este estudio fue determinar las propiedades inmunes del cáncer de recto mucinoso e investigar el grado de infiltración de linfocitos en esta cohorte.DISEÑO:Este es un estudio de cohorte retrospectivo que involucró la tinción de inmunofluorescencia multiplexada de micromatrices tumorales.AJUSTES:Las muestras se originaron en un solo hospital docente universitario.PACIENTES:Nuestra cohorte incluyó 15 casos de cáncer de recto mucinoso y 43 casos de cáncer de recto no mucinosoPRINCIPALES MEDIDAS DE RESULTADO:Las células inmunitarias se clasificaron y cuantificaron. Se compararon los recuentos de células inmunitarias entre cohortes mucinosas y no mucinosas. Se evaluó la expresión del marcador inmunitario dentro del tejido epitelial tumoral para determinar el grado de infiltración de linfocitos.RESULTADOS:Se encontró que las células T citotóxicas ( p = 0,022) y reguladoras ( p = 0,010) estaban sobrerrepresentadas en la cohorte mucinosa en comparación con el grupo no mucinoso. También se encontró que la expresión de PD-1 era significativamente mayor en el grupo mucinoso ( p = 0,001). La expresión de CD3 ( p = 0,001) y CD8 ( p = 0,054) dentro del epitelio tumoral también fue mayor en el grupo mucinoso, lo que sugiere una infiltración inmunitaria adecuada a pesar de la presencia de mucina. En nuestro análisis, no se encontró que el estado de inestabilidad de los microsatélites sea un predictor de la expresión del marcador inmunitario.LIMITACIONES:El tamaño relativamente pequeño de la cohorte.CONCLUSIONES:El cáncer rectal mucinoso se asocia con un microambiente tumoral rico en inmunidad, que no se asoció con el estado de inestabilidad de microsatélites. Consulte el Video del Resumen en http://links.lww.com/DCR/C65 . (Traducción- Dr. Yesenia Rojas-Khalil ).

Increased Fusobacterium tumoural abundance affects immunogenicity in mucinous colorectal cancer and may be associated with improved clinical outcome

There is currently an urgent need to identify factors predictive of immunogenicity in colorectal cancer (CRC). Mucinous CRC is a distinct histological subtype of CRC, associated with a poor response to chemotherapy. Recent evidence suggests the commensal facultative anaerobe Fusobacterium may be especially prevalent in mucinous CRC. The objectives of this study were to assess the association of Fusobacterium abundance with immune cell composition and prognosis in mucinous CRC. Our study included two independent colorectal cancer patient cohorts, The Cancer Genome Atlas (TCGA) cohort, and a cohort of rectal cancers from the Beaumont RCSI Cancer Centre (BRCC). Multiplexed immunofluorescence staining of a tumour microarray (TMA) from the BRCC cohort was undertaken using Cell DIVE technology. Our cohorts included 87 cases (13.3%) of mucinous and 565 cases (86.7%) of non-mucinous CRC. Mucinous CRC in the TCGA dataset was associated with an increased proportion of CD8 + lymphocytes (p = 0.018), regulatory T-cells (p = 0.001) and M2 macrophages (p = 0.001). In the BRCC cohort, mucinous RC was associated with enhanced CD8 + lymphocyte (p = 0.022), regulatory T-cell (p = 0.047), and B-cell (p = 0.025) counts. High Fusobacterium abundance was associated with an increased proportion of CD4 + lymphocytes (p = 0.031) and M1 macrophages (p = 0.006), whilst M2 macrophages (p = 0.043) were under-represented in this cohort. Patients with increased Fusobacterium relative abundance in our mucinous CRC TCGA cohort tended to have better clinical outcomes (DSS: likelihood ratio p = 0.04, logrank p = 0.052). Fusobacterium abundance may be associated with improved outcomes in mucinous CRC, possibly due to a modulatory effect on the host immune response. KEY MESSAGES: • Increased Fusobacterium relative abundance was not found to be associated with microsatellite instability in mucinous CRC. • Increased Fusobacterium relative abundance was associated with an M2/M1 macrophage switch, which is especially significant in mucinous CRC, where M2 macrophages are overexpressed. • Increased Fusobacterium relative abundance was associated with a significant improvement in disease specific survival in mucinous CRC. • Our findings were validated at a protein level within our own in house mucinous and non-mucinous rectal cancer cohorts.

Rectal cancer–specific subtyping using transcriptomics datasets derived from treatment-naive patients to assess novel prognostic signatures and key differences to CMS-based subtyping

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Background: Molecular subtyping in colorectal cancer provided novel insights into tumour heterogeneity and delivered new prognostic signatures. Existing methods (such as CMS-based subtyping) were generated without much consideration of differences in expression profiles between colon and rectal cancer tissues. Moreover, stage 2 and 3 rectal cancer patients often receive neo-adjuvant radio-chemotherapy which may impact on gene expression when determined from resection samples. Methods: We investigated possible differences between treatment-naive colon and rectal cancers at the molecular level. We collected mRNA expression profiles for rectal and colon cancer samples available from Gene Expression Omnibus (GEO) database (n=2139) and applied batch-effect correction using ComBat. Results: To explore whether CMS subtypes changed after neoadjuvant chemoradiation in rectal cancers, we analysed rectal tumour samples from 40 patients where both pre-operative biopsies and resections after chemoradiotherapy were available. More than half of samples shifted from CMS1-3 to CMS4 after patients received chemoradiotherapy. We therefore focused our further analysis on treatment-naive rectal cancers. We observed that CMS-based subtyping showed different prognostic potential in treatment-naïve colon vs. rectal cancers. Rectal cancers had significantly better disease-free survival (DFS) when assigned to CMS 2 or 4 compared to colon cancers. This suggested differences in disease biology that were not captured by CMS subtyping. We next aimed to identify molecular subtypes in rectal cancers, and identified three prevalent rectal-specific subtypes (RSS) by applying hierarchical clustering in 182 untreated rectal cancer samples. We used gene co-expression network analysis to define functional gene modules to identify these subtypes. Based on the gene modules’ signatures, we built a classifier to predict our new subtypes in different transcriptomics datasets (n=692). We observed that RSS1 had better disease-free survival (DFS), whereas RSS2 exhibited worse short-term DFS (less than 3 years) and RSS3 showed worse long-term DFS (3+ years). We discovered the deactivation of EGFR, MAPK and WNT pathways on RSS3 as well as high CD8+ infiltration and low CD4+ counts in these tumours. RSS2 exhibits low plasma cell and regulatory T-cell abundance and high activations of TGF-β, NF-κB, and TNF-α. We also observed high EMT, angiogenesis and inflammatory response in this subtype. Lastly, RSS1 showed high expression on MYC target and low activity on angiogenesis genes. Moreover, the immune and inflammatory responses were also lower than in the other subtypes. Conclusions: Rectal-specific subtypes are of prognostic importance and provide new insight into molecular disease pathways and potential targets.

Step up to health, Nigeria! utilizing information from abuja's world cancer day walks for equity-based cancer prevention interventions

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Background: Abuja, Nigeria’s annual World Cancer Day Walk (WCDW) is a tool for promoting public awareness of cancer risk factors, preventative lifestyle strategies, and the importance of early screening as critical elements of prevention and control. The day includes physical activities (walk, race, ride, skate, cycle, marathon), as well as health education and free breast cancer, cervical, and prostate screenings. The effectiveness of the event to attract the most vulnerable Nigerian populations has not been studied. Aim: To determine the social-demographic characteristics of participants and evaluate the impact of outreach campaigns. Methods: Approximately 2,000 Nigerians attended Abuja WCDW on February 1, 2020. A similar number attended Abuja WCDW on February 5, 2022. Trained research assistants recruited participants to complete a one-sheet questionnaire that assessed basic demographic, social, and lifestyle information. Participants were given informed consent. In 2020, 237 (11%) participants, aged 18-68 years voluntarily completed survey (ClinicalTrials #NCT04248881). In 2022, 111 (6%), aged 17-74 years voluntarily completed survey (ClinicalTrials #NCT05239325). Note: In 2021, Abuja WCDW was canceled due to COVID. Results: In 2020, the mean age for participants was 28; SD 7.71. Sixty-eight percent were women. Eighty-seven percent had at least an undergraduate education. Of the 237 participants, 65% reported that they attended to obtain free cancer screening. More than 50% reported they had no health insurance. Of those insured, more had National Health Insurance Scheme (NHIS) than private insurance. The average body mass index (BMI) was between 24-28; BMI was highest among the mid-20 age group. Lifestyle data revealed more men than women were concerned with their health; those with health worries were more likely to have had cancer screening at the event. The 2022 WCDW data were being analyzed at the time of abstract submission; findings will be presented at the meeting. Analysis: Data from 2020 revealed participants are predominately associated with a lower risk of developing cancer. They have higher levels of knowledge about cancer and lifestyle/health-related behaviors beneficial for early detection and prevention. WCDW is a great avenue for cancer awareness/lifestyle prevention interventions yet there is an urgent need to evaluate efficacy of current outreach to target underserved members of Nigerian population: those with lower levels of education, unemployed, lower income, and without insurance. Conclusions: Attendees in 2020 are younger people of higher socioeconomic status with lifestyle practices that could reduce cancer risk. If our 2022 data are similar, we must elaborate better strategies to reach populations at greater risk and encourage them to attend future events to have more impactful lifestyle/prevention outcomes. Clinical trial information: NCT05239325.