The interleukin 22 pathway interacts with mutant KRAS to promote poor prognosis in colon cancer

Purpose: The cytokine IL22 promotes tumor progression in murine models of colorectal cancer. However, the clinical significance of IL22 in human colorectal cancer remains unclear. We sought to determine whether the IL22 pathway is associated with prognosis in human colorectal cancer, and to identify mechanisms by which IL22 can influence disease progression.

Experimental Design: Transcriptomic data from stage II/III colon cancers in independent discovery (GSE39582 population-based cohort, N = 566) and verification (PETACC3 clinical trial, N = 752) datasets were used to investigate the association between IL22 receptor expression (encoded by the genes IL22RA1 and IL10RB), tumor mutation status, and clinical outcome using Cox proportional hazard models. Functional interactions between IL22 and mutant KRAS were elucidated using human colorectal cancer cell lines and primary tumor organoids.

Results: Transcriptomic analysis revealed a poor-prognosis subset of tumors characterized by high expression of IL22RA1, the alpha subunit of the heterodimeric IL22 receptor, and KRAS mutation [relapse-free survival (RFS): HR = 2.93, P = 0.0006; overall survival (OS): HR = 2.45, P = 0.0023]. KRAS mutations showed a similar interaction with IL10RB and conferred the worst prognosis in tumors with high expression of both IL22RA1 and IL10RB (RFS: HR = 3.81, P = 0.0036; OS: HR = 3.90, P = 0.0050). Analysis of human colorectal cancer cell lines and primary tumor organoids, including an isogenic cell line pair that differed only in KRAS mutation status, showed that IL22 and mutant KRAS cooperatively enhance cancer cell proliferation, in part through augmentation of the Myc pathway.

Conclusions: Interactions between KRAS and IL22 signaling may underlie a previously unrecognized subset of clinically aggressive colorectal cancer that could benefit from therapeutic modulation of the IL22 pathway.

Journal Clinical Cancer Research
Authors Sarah McCuaig et al
DATE August 2020
Prognostic value of histopathological DCIS features in a large scale international interrater reliability study

Purpose: For optimal management of ductal carcinoma in situ (DCIS), reproducible histopathological assessment is essential to distinguish low-risk from high-risk DCIS. Therefore, we analyzed interrater reliability of histopathological DCIS features and assessed their associations with subsequent ipsilateral invasive breast cancer (iIBC) risk.

Methods: Using a case-cohort design, reliability was assessed in a population-based, nationwide cohort of 2767 women with screen-detected DCIS diagnosed between 1993 and 2004, treated by breast-conserving surgery with/without radiotherapy (BCS ± RT) using Krippendorff’s alpha (KA) and Gwet’s AC2 (GAC2). Thirty-eight raters scored histopathological DCIS features including grade (2-tiered and 3-tiered), growth pattern, mitotic activity, periductal fibrosis, and lymphocytic infiltrate in 342 women. Using majority opinion-based scores for each feature, their association with subsequent iIBC risk was assessed using Cox regression.

Results: Interrater reliability of grade using various classifications was fair to moderate, and only substantial for grade 1 versus 2 + 3 when using GAC2 (0.78). Reliability for growth pattern (KA 0.44, GAC2 0.78), calcifications (KA 0.49, GAC2 0.70) and necrosis (KA 0.47, GAC2 0.70) was moderate using KA and substantial using GAC2; for (type of) periductal fibrosis and lymphocytic infiltrate fair to moderate estimates were found and for mitotic activity reliability was substantial using GAC2 (0.70). Only in patients treated with BCS-RT, high mitotic activity was associated with a higher iIBC risk in univariable analysis (Hazard Ratio (HR) 2.53, 95% Confidence Interval (95% CI) 1.05–6.11); grade 3 versus 1 + 2 (HR 2.64, 95% CI 1.35–5.14) and a cribriform/solid versus flat epithelial atypia/clinging/(micro)papillary growth pattern (HR 3.70, 95% CI 1.34–10.23) were independently associated with a higher iIBC risk.

Conclusions: Using majority opinion-based scores, DCIS grade, growth pattern, and mitotic activity are associated with iIBC risk in patients treated with BCS-RT, but interrater variability is substantial. Semi-quantitative grading, incorporating and separately evaluating nuclear pleomorphism, growth pattern, and mitotic activity, may improve the reliability and prognostic value of these features.

Journal Breast Cancer Research and Treatment
Authors Emma J. Groen et al
DATE 30 July 2020
Fusobacterium nucleatum persistence and risk of recurrence after preoperative treatment in locally advanced rectal cancer

Background: Accumulating evidence has identified Fusobacterium as an important pathogenic gut bacterium associated with colorectal cancer. Nevertheless, only limited data exist about the role of this bacterium in locally advanced rectal cancer (LARC). In this study, we quantified Fusobacterium nucleatum in untreated and post-neoadjuvant chemoradiotherapy (nCRT) samples from LARC patients and investigated its association with therapy response and survival.

Patients and methods: A total of 254 samples from 143 patients with rectal adenocarcinomas were analyzed for the presence and abundance of F. nucleatum using RNA in situ hybridization and digital image analysis. Assay accuracy was determined using infected cell lines and tumor samples with available quantitative PCR data. We studied the impact of F. nucleatum load on pathologic complete response and relapse-free survival. Treatment-induced changes were evaluated in paired pre- and post-nCRT samples (n = 71). Finally, tumor microenvironment changes during nCRT were assessed in paired samples (n = 45) by immune contexture analysis.

Results: F. nucleatum tissue levels by RNA in situ hybridization strongly correlated with quantitative PCR (r = 0.804, P < 0.001). F. nucleatum abundance was higher in untreated [median, 7.4; 95% confidence interval (3.7–16.2)] compared with treated [median, 1.6; 95% confidence interval (1.3–2.4)] tumors (P <0.001) with 58% (73/126) and 26% (22/85) positive tumors, respectively (P < 0.001). Baseline F. nucleatum levels were not associated with pathologic complete response. F. nucleatum positivity after nCRT, but not baseline status, significantly increased risk of relapse [hazard ratio = 7.5, 95% confidence interval (3.0–19.0); P < 0.001]. Tumors that turned F. nucleatum-negative after nCRT had a strong increase in CD8+ T cells post-nCRT (P < 0.001), while those that persisted F. nucleatum-positive after nCRT lacked CD8+ T cells induction in post-nCRT samples compared with baseline (P = 0.69).

Conclusion: F. nucleatum persistence post-nCRT is associated with high relapse rates in LARC, potentially linked to suppression of immune cytotoxicity.

Journal Annals of Oncology
Authors G. Serna et al
DATE 19 June 2020
Metabolic fingerprinting links oncogenic PIK3CA with enhanced arachidonic acid-derived eicosanoids

Oncogenic transformation is associated with profound changes in cellular metabolism, but whether tracking these can improve disease stratification or influence therapy decision-making is largely unknown. Using the iKnife to sample the aerosol of cauterized specimens, we demonstrate a new mode of real-time diagnosis, coupling metabolic phenotype to mutant PIK3CA genotype. Oncogenic PIK3CA results in an increase in arachidonic acid and a concomitant overproduction of eicosanoids, acting to promote cell proliferation beyond a cell-autonomous manner. Mechanistically, mutant PIK3CA drives a multimodal signaling network involving mTORC2-PKCz-mediated activation of the calcium-dependent phospholipase A2 (cPLA2). Notably, inhibiting cPLA2 synergizes with fatty acid-free diet to restore immunogenicity and selectively reduce mutant PIK3CA-induced tumorigenicity. Besides highlighting the potential for metabolic phenotyping in stratified medicine, this study reveals an important role for activated PI3K signaling in regulating arachidonic acid metabolism, uncovering a targetable metabolic vulnerability that largely depends on dietary fat restriction.

Team Rosetta
Journal Cell
Authors Nikos Koundouros et al
DATE 18 June 2020
Universal sample preparation unlocking multimodal molecular tissue imaging

A new tissue sample embedding and processing method is presented that provides downstream compatibility with numerous different histological, molecular biology, and analytical techniques. The methodology is based on the low temperature embedding of fresh frozen specimens into a hydrogel matrix composed of hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) and sectioning using a cryomicrotome. The hydrogel was expected not to interfere with standard tissue characterization methods, histologically or analytically. We assessed the compatibility of this protocol with various mass spectrometric imaging methods including matrix-assisted laser desorption ionization (MALDI), desorption electrospray ionization (DESI) and secondary ion mass spectrometry (SIMS). We also demonstrated the suitability of the universal protocol for extraction based molecular biology techniques such as rt-PCR. The integration of multiple analytical modalities through this universal sample preparation protocol offers the ability to study tissues at a systems biology level and directly linking results to tissue morphology and cellular phenotype.

Team Rosetta
Journal Analytical Chemistry
Authors Andreas Dannhorn et al
DATE 10 June 2020