Second-line therapy with nivolumab plus ipilimumab for older patients with oesophageal squamous cell cancer (RAMONA): a multicentre, open-label phase 2 trial.

BACKGROUND: The overall survival of patients with advanced and refractory oesophageal squamous cell carcinoma, mostly aged 65 years and older, is poor. Treatment with PD-1 antibodies showed improved progression-free survival and overall survival. We assessed the safety and efficacy of combined nivolumab and ipilimumab therapy in this population. METHODS: This multicentre, open-label, phase 2 trial done in 32 sites in Germany included patients aged 65 years and older with oesophageal squamous cell carcinoma and disease progression or recurrence following first-line therapy. Patients were treated with nivolumab (240 mg fixed dose once every 2 weeks, intravenously) in the safety run-in phase and continued with nivolumab and ipilimumab (nivolumab 240 mg fixed dose once every 2 weeks and ipilimumab 1 mg/kg once every 6 weeks, intravenously). The primary endpoint was overall survival, which was compared with a historical cohort receiving standard chemotherapy in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT03416244. FINDINGS: Between March 2, 2018, and Aug 20, 2020, we screened 75 patients with advanced oesophageal squamous cell carcinoma. We enrolled 66 patients (50 [76%] men and 16 [24%] women; median age 70·5 years [IQR 67·0-76·0]), 44 (67%) of whom received combined nivolumab and ipilimumab therapy and 22 (33%) received nivolumab alone. Median overall survival time at the prespecified data cutoff was 7·2 months (95% CI 5·7-12·4) and significantly higher than in a historical cohort receiving standard chemotherapy (p=0·0063). The most common treatment-related adverse events were fatigue (12 [29%] of 42), nausea (11 [26%]), and diarrhoea (ten [24%]). Grade 3-5 treatment-related adverse events occurred in 13 (20%) of 66 patients. Treatment-related death occurred in one patient with bronchiolitis obliterans while on nivolumab and ipilimumab treatment. INTERPRETATION: Patients aged at least 65 years, with advanced oesophageal squamous cell carcinoma might benefit from combined nivolumab and ipilimumab therapy in second-line treatment. FUNDING: Bristol Myers Squibb.

The drug-induced phenotypic landscape of colorectal cancer organoids.

Patient-derived organoids resemble the biology of tissues and tumors, enabling ex vivo modeling of human diseases. They have heterogeneous morphologies with unclear biological causes and relationship to treatment response. Here, we use high-throughput, image-based profiling to quantify phenotypes of over 5 million individual colorectal cancer organoids after treatment with >500 small molecules. Integration of data using multi-omics modeling identifies axes of morphological variation across organoids: Organoid size is linked to IGF1 receptor signaling, and cystic vs. solid organoid architecture is associated with LGR5 + stemness. Treatment-induced organoid morphology reflects organoid viability, drug mechanism of action, and is biologically interpretable. Inhibition of MEK leads to cystic reorganization of organoids and increases expression of LGR5, while inhibition of mTOR induces IGF1 receptor signaling. In conclusion, we identify shared axes of variation for colorectal cancer organoid morphology, their underlying biological mechanisms, and pharmacological interventions with the ability to move organoids along them.

Expression of the EGFR-RAS Inhibitory Proteins DOK1 and MTMR7 and its Significance in Colorectal Adenoma and Adenoma Recurrence.

BACKGROUND AND AIMS: Colorectal adenomas are precursor lesions for colorectal cancer (CRC), a major cause of cancer-related death. Despite all molecular insights, there are still unknown variables in the development of CRC as well as uncertainties regarding adenoma recurrence after resection. We aimed to characterize the expression of docking protein 1 (DOK1) and myotubularin-related protein 7 (MTMR7), which share inhibiting functions on EGFR-RAS-signalling, a major oncogenic driver in CRC, and their association with clinical variables and adenoma recurrence. METHODS: This observational study is based on clinical data obtained from patients who underwent routine endoscopy and consecutive follow-up examinations. Immunohistochemistry was conducted both in dysplastic tissue and adjacent non-dysplastic mucosa followed by microscopical assessment. Recurrence was differentiated between local, segmental and distant relapse. RESULTS: A total of 56 patients (23 females) gathering 96 adenomas/polyps were included. 36 patients experienced a metachronous lesion, 23 patients had simultaneous lesions in their index endoscopy. Female patients showed lower levels of MTMR7 in adenomas (p=0.0318). Adenomas of young patients showed lower DOK1 than those of older patients (p=0.0469). Big adenomas showed a higher expression of DOK1 than small lesions (p=0.0044). In serrated lesions, DOK1 was reduced (p=0.0026) and correlated with the quantity of lesions (p < 0.001). MTMR7 was significantly reduced in distant (p=0.05) and local segmental recurrence (p=0.0362), while DOK1 showed higher expression in recurrence (p=0.0291). CONCLUSIONS: We found ambivalent results regarding the role of the markers as potential tumor suppressors, implying a context-dependent function of these molecules which might change in the course of time. DOK1 may play an inhibiting role in the serrated pathway. Remarkably, molecular markers have the potential to predict recurrence, since a combined expression analysis of high DOK1 and low MTMR7 correlated with the likelihood of segmental adenoma recurrence.

PPARγ induces PD-L1 expression in MSS+ colorectal cancer cells.

Only a small subset of colorectal cancer (CRC) patients benefits from immunotherapies, comprising blocking antibodies (Abs) against checkpoint receptor "programmed-cell-death-1" (PD1) and its ligand (PD-L1), because most cases lack the required mutational burden and neo-antigen load caused by microsatellite instability (MSI) and/or an inflamed, immune cell-infiltrated PD-L1+ tumor microenvironment. Peroxisome proliferator-activated-receptor-gamma (PPARγ), a metabolic transcription factor stimulated by anti-diabetic drugs, has been previously implicated in pre/clinical responses to immunotherapy. We therefore raised the hypothesis that PPARγ induces PD-L1 on microsatellite stable (MSS) tumor cells to enhance Ab-target engagement and responsiveness to PD-L1 blockage. We found that PPARγ-agonists upregulate PD-L1 mRNA/protein expression in human gastrointestinal cancer cell lines and MSS+ patient-derived tumor organoids (PDOs). Mechanistically, PPARγ bound to and activated DNA-motifs similar to cognate PPARγ-responsive-elements (PPREs) in the proximal -2 kb promoter of the human PD-L1 gene. PPARγ-agonist reduced proliferation and viability of tumor cells in co-cultures with PD-L1 blocking Ab and lymphokine-activated killer cells (LAK) derived from the peripheral blood of CRC patients or healthy donors. Thus, metabolic modifiers improved the antitumoral response of immune checkpoint Ab, proposing novel therapeutic strategies for CRC.

Myotubularin-related protein 7 activates peroxisome proliferator-activated receptor-gamma.

Peroxisome proliferator-activated receptor-gamma (PPARγ) is a transcription factor drugable by agonists approved for treatment of type 2 diabetes, but also inhibits carcinogenesis and cell proliferation in vivo. Activating mutations in the Kirsten rat sarcoma viral oncogene homologue (KRAS) gene mitigate these beneficial effects by promoting a negative feedback-loop comprising extracellular signal-regulated kinase 1/2 (ERK1/2) and mitogen-activated kinase kinase 1/2 (MEK1/2)-dependent inactivation of PPARγ. To overcome this inhibitory mechanism, we searched for novel post-translational regulators of PPARγ. Phosphoinositide phosphatase Myotubularin-Related-Protein-7 (MTMR7) was identified as cytosolic interaction partner of PPARγ. Synthetic peptides were designed resembling the regulatory coiled-coil (CC) domain of MTMR7, and their activities studied in human cancer cell lines and C57BL6/J mice. MTMR7 formed a complex with PPARγ and increased its transcriptional activity by inhibiting ERK1/2-dependent phosphorylation of PPARγ. MTMR7-CC peptides mimicked PPARγ-activation in vitro and in vivo due to LXXLL motifs in the CC domain. Molecular dynamics simulations and docking predicted that peptides interact with the steroid receptor coactivator 1 (SRC1)-binding site of PPARγ. Thus, MTMR7 is a positive regulator of PPARγ, and its mimicry by synthetic peptides overcomes inhibitory mechanisms active in cancer cells possibly contributing to the failure of clinical studies targeting PPARγ.

Complete Remission of Metastatic HER2+ Oesophagogastric Junctional Adenocarcinoma under long-term Trastuzumab Treatment.

Metastatic gastric cancer (GC) and oesophagogastric junctional (OGJ) adenocarcinoma have a poor clinical outcome with a high worldwide burden of disease. A 65-year old male patient with microcytic anemia was diagnosed with stage IV OGJ adenocarcinoma with multiple liver metastases. Immunohistochemical analysis revealed a high expression of HER2 (3+). Palliative chemotherapy with FLOT (oxaliplatin, 5-fluorouracil, leucovorin and docetaxel) in combination with trastuzumab was initiated. Due to severe adverse events, the therapy was de-escalated to trastuzumab monotherapy after six months of treatment. Initial restaging revealed partial response after the combination therapy of FLOT with trastuzumab. After reduction to trastuzumab monotherapy, the disease remained stable for two years until radiological complete response was observed. Trastuzumab monotherapy was continued for another two years to maintain complete response. Eleven months after the discontinuation of the therapy, no recurrence of the disease was detected. In conclusion, complete response can be achieved under trastuzumab monotherapy in exceptional responders.

Docking protein-1 promotes inflammatory macrophage signaling in gastric cancer.

Docking protein-1 (DOK1) is a tumor suppressor frequently lost in malignant cells, however, it retains the ability to control activities of immune receptors in adjacent stroma cells of the tumor microenvironment. We therefore hypothesized that addressing DOK1 may be useful for cancer immunotherapy. DOK1 mRNA and DOK1 protein expression were downregulated in tumor cells of gastric cancer patients (n = 249). Conversely, its expression was up-regulated in cases positive for Epstein Barr Virus (EBV+) together with genes related to macrophage biology and targets of clinical immunotherapy such as programmed-cell-death-ligand-1 (PD-L1). Notably, high DOK1 positivity in stroma cells conferred poor prognosis in patients and correlated with high levels of inducible nitric oxide synthase in CD68+ tumor-associated macrophages. In macrophages derived from human monocytic leukemia cell lines, DOK1 (i) was inducible by agonists of the anti-diabetic transcription factor peroxisome proliferator-activated receptor-gamma (PPARγ), (ii) increased polarization towards an inflammatory phenotype, (iii) augmented nuclear factor-κB-dependent transcription of pro-inflammatory cytokines and (iv) reduced PD-L1 expression. These properties empowered DOK1+ macrophages to decrease the viability of human gastric cancer cells in contact-dependent co-cultures. DOK1 also reduced PD-L1 expression in human primary blood monocytes. Our data propose that the drugability of DOK1 may be exploited to reprogram myeloid cells and enforce the innate immune response against EBV+ human gastric cancer.

Detection of mutational patterns in cell-free DNA of colorectal cancer by custom amplicon sequencing.

Monitoring the mutational patterns of solid tumors during cancer therapy is a major challenge in oncology. Analysis of mutations in cell-free (cf) DNA offers a noninvasive approach to detect mutations that may be prognostic for disease survival or predictive for primary or secondary drug resistance. A main challenge for the application of cfDNA as a diagnostic tool is the diverse mutational landscape of cancer. Here, we developed a flexible end-to-end experimental and bioinformatic workflow to analyze mutations in cfDNA using custom amplicon sequencing. Our approach relies on open-software tools to select primers suitable for multiplex PCR using minimal cfDNA as input. In addition, we developed a robust linear model to identify specific genetic alterations from sequencing data of cfDNA. We used our workflow to design a custom amplicon panel suitable for detection of hotspot mutations relevant for colorectal cancer and analyzed mutations in serial cfDNA samples from a pilot cohort of 34 patients with advanced colorectal cancer. Using our method, we could detect recurrent and patient-specific mutational patterns in the majority of patients. Furthermore, we show that dynamic changes of mutant allele frequencies in cfDNA correlate well with disease progression. Finally, we demonstrate that sequencing of cfDNA can reveal mechanisms of resistance to anti-Epidermal Growth Factor Receptor(EGFR) antibody treatment. Thus, our approach offers a simple and highly customizable method to explore genetic alterations in cfDNA.

A multicenter open-label phase II trial to evaluate nivolumab and ipilimumab for 2nd line therapy in elderly patients with advanced esophageal squamous cell cancer (RAMONA).

BACKGROUND: Advanced esophageal squamous cell cancer (ESCC) is frequently diagnosed in elderly patients. The impact of 2nd line chemotherapy is poorly defined. Recent data demonstrated effectiveness of checkpoint inhibitors in different squamous cell carcinomas. Therefore, we assess combined nivolumab/ipilimumab as 2nd line therapy in elderly ESCC patients. METHODS: RAMONA is a multicenter open-label phase II trial. The primary objective is to demonstrate a significant survival benefit of nivolumab/ipilimumab in advanced ESCC compared to historical data of standard chemotherapy. Primary endpoint is therefore overall survival (OS). Major secondary objective is the evaluation of tolerability. Time to QoL deterioration will thus be determined as key secondary endpoint. Further secondary endpoints are tumor response, PFS and safety. We aim to recruit a total of n = 75 subjects that have to be > 65 years old. Eligibility is determined by the geriatric status (G8 screening and Deficit Accumulation Frailty Index (DAFI)). A safety assessment will be performed after a 3 cycle run-in phase of nivolumab (240 mg Q2W) to justify escalation for eligible patients to combined nivolumab (240 mg Q2W) and ipilimumab (1 mg/kg Q6W), while the other patients will remain on nivolumab only. RAMONA also includes translational research sub-studies to identify predictive biomarkers, including PD-1 and PD-L1 evaluation at different time points, establishment of organoid cultures and microbiome analyses for response prediction. DISCUSSION: The RAMONA trial aims to implement checkpoint inhibitors for elderly patients with advanced ESCC as second line therapy. Novel biomarkers for checkpoint-inhibitor response are analyzed in extensive translational sub-studies. TRIAL REGISTRATION: EudraCT Number: 2017-002056-86 ; NCT03416244 , registered: 31.1.2018.

Therapeutic drug monitoring (TDM) of 5-fluorouracil (5-FU): new preanalytic aspects.

Background 5-Fluorouracil (5-FU) is frequently used for the treatment of gastrointestinal tumors. The pharmacological effect of 5-FU is influenced by genetic polymorphisms as well as differently dosed regimens. Currently, 5-FU is generally administered as a continuous infusion via an implanted port system using a body surface area (BSA)-based dose calculation. In order to optimize treatment, the area under the curve (AUC) can be estimated to allow for individual dose adjustment. A 5-FU AUC range between 20 and 30 [mg×h×L] is recommended. The aim of the current study was to assess if blood for AUC analysis could also be drawn at the side where the port system had been placed. Methods We collected EDTA blood samples of patients receiving infusional 5-FU simultaneously from different sampling points (right/left cubital vein). 5-FU concentrations were measured in a steady-state equilibrium based on nanoparticle immunoassay (My5-FU; Saladax). Results A total of 39 patients took part in this study. About half of the patients did not reach the target 5-FU concentration window (37% were under- and 16% of the patients were overdosed). Calculated median AUC was 23.3 for the right arm (range 5.8-59.4) and a median of 23.4 for the left arm (range 5.3-61.0). AUC values showed no difference between right compared to left arms (p=0.99). Conclusions In all, these results confirm that a high percentage of patients are not treated with 5-FU doses reaching suggested AUC levels of 20-30. The location of venepuncture, however, had no impact on the results of plasma 5-FU concentration.

Checkpoints and beyond - Immunotherapy in colorectal cancer.

Immunotherapy is the latest revolution in cancer therapy. It continues to show impressive results in malignancies like melanoma and others. At least so far, effects are modest in colorectal cancer (CRC) and only a subset of patients benefits from already approved checkpoint inhibitors. In this review, we discuss major hurdles of immunotherapy like the immunosuppressive niche and low immunogenicity of CRC next to current achievements of checkpoint inhibitors, interleukin treatment and adoptive cell transfer (dendritic cells/cytokine induced killer cells, tumor infiltrating lymphocytes, chimeric antigen receptor cells, T cell receptor transfer) in pre-clinical models and clinical trials. We intensively examine approaches to overcome low immunogenicity by combination of different therapies and address future strategies of therapy as well as the need of predictive factors in this emerging field of precision medicine.

Spatial Distribution of Endogenous Tissue Protease Activity in Gastric Carcinoma Mapped by MALDI Mass Spectrometry Imaging.

Aberrant protease activity has been implicated in the etiology of various prevalent diseases including neurodegeneration and cancer, in particular metastasis. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has recently been established as a key technology for bioanalysis of multiple biomolecular classes such as proteins, lipids, and glycans. However, it has not yet been systematically explored for investigation of a tissue's endogenous protease activity. In this study, we demonstrate that different tissues, spray-coated with substance P as a tracer, digest this peptide with different time-course profiles. Furthermore, we reveal that distinct cleavage products originating from substance P are generated transiently and that proteolysis can be attenuated by protease inhibitors in a concentration-dependent manner. To show the translational potential of the method, we analyzed protease activity of gastric carcinoma in mice. Our MSI and quantitative proteomics results reveal differential distribution of protease activity - with strongest activity being observed in mouse tumor tissue, suggesting the general applicability of the workflow in animal pharmacology and clinical studies.

A multicenter phase 4 geriatric assessment directed trial to evaluate gemcitabine +/- nab-paclitaxel in elderly pancreatic cancer patients (GrantPax).

BACKGROUND: In the group of elderly patients (≥70 years) with metastatic pancreatic ductal adenocarcinoma (mPDAC), it is not known who benefits from intensive 1st line nab-paclitaxel/gemcitabine (nab-p/gem) combination chemotherapy or who would rather suffer from increased toxicity. We aim to determine whether treatment individualization by comprehensive geriatric assessments (CGAs) improves functional outcome of the patients. METHODS/DESIGN: GrantPax is a multicenter, open label phase 4 interventional trial. We use a CGA to stratify elderly patients into three parallel treatment groups (n = 45 per arm): 1) GOGO (nab-p/gem), 2) SLOWGO (gem mono) or 3) FRAIL (best supportive care). After the 1st cycle of chemotherapy (or 4 weeks in FRAIL group) another CGA and safety assessment is performed. CGA-stratified patients may not decline in their CGA performance in response to the first cycle of chemotherapy (primary objective), measured as a loss of 5 points or less in Barthels activities of daily living. Based on the second CGA, patients are re-assigned to their definite treatment arm and undergo further CGAs to monitor the course of treatment. Secondary endpoints include CGA scores during the course of therapy (CGA1-4), response rates, safety and survival rates. DISCUSSION: GrantPax is the first trial implementing a CGA-driven treatment to personalize therapy for elderly patients with pancreatic cancer. This may lead to standardization of therapy decisions for elderly patients and may optimize standard of care for this increasing group of patients. TRIAL REGISTRATION: NCT02812992 , registered 24.06.2016.

PPARγ-activation increases intestinal M1 macrophages and mitigates formation of serrated adenomas in mutant KRAS mice.

To identify novel hubs for cancer immunotherapy, we generated C57BL/6J mice with concomitant deletion of the drugable transcription factor PPARγ and transgenic overexpression of the mutant KRASG12V oncogene in enterocytes. Animals developed epithelial hyperplasia, transmural inflammation and serrated adenomas in the small intestine with infiltration of CD3+ FOXP3+ T-cells and macrophages into the lamina propria of the non-malignant mucosa. Within serrated polyps, CD3+ CD8+ T-cells and phosphorylated ERK1/2 were reduced and the senescence marker P21 and macrophage counts up-regulated, indicative of an immunosuppressive tissue microenvironment. Treatment of mutant KRASG12V mice with the PPARγ-agonist rosiglitazone augmented M1 macrophage numbers, reduced IL4 expression and diminished polyp load in mice. Rosiglitazone also promoted M1 polarisation of human THP1-derived macrophages and decreased Il4 mRNA in isolated murine lymphocytes. Thus, inhibition of the oncogenic driver mutant RAS by PPARγ in epithelial and immune cell compartments may be a future target for the prevention or treatment of human malignancies associated with intestinal inflammation.

Insulin-like growth factor 2 expression in prostate cancer is regulated by promoter-specific methylation.

Deregulation of the insulin-like growth factor (IGF) axis and dysbalance of components of the IGF system as potential therapeutic targets have been described in different tumor types. IGF2 is a major embryonic growth factor and an important activator of IGF signaling. It is regulated by imprinting in a development- and tissue-dependent manner and has been implicated in a broad range of malignancies including prostate cancer (PCa). Loss of imprinting (LOI) usually results in bi-allelic gene expression and increased levels of IGF2. However, the regulatory mechanisms and the pathophysiological impact of altered IGF2 expression in PCa remain elusive. Here, we show that in contrast to many other tumors, IGF2 mRNA and protein levels were decreased in 80% of PCa in comparison with non-neoplastic adjacent prostate and were independent of LOI status. Instead, IGF2 expression in both tumors and adjacent prostate depended on preferential usage of the IGF2 promoters P3 and P4. Decreased IGF2 expression in tumors was strongly related to hypermethylation of these two promoters. Methylation of the A region in promoter P4 correlated specifically with IGF2 expression in the 20% of PCa where IGF2 was higher in tumors than in adjacent prostate. We conclude that IGF2 is downregulated in most PCa and may be particularly relevant during early stages of tumor development or during chemotherapy and androgen deprivation. PCa differs from other tumors in that IGF2 expression is mainly regulated through methylation of promoter-specific and not by imprinting. Targeting of promoter-specific regions may have relevance for the adjuvant treatment of PCa.

Epigenetic silencing of tumor suppressor candidate 3 confers adverse prognosis in early colorectal cancer.

Colorectal cancer (CRC) is a biologically and clinically heterogeneous disease. Even though many recurrent genomic alterations have been identified that may characterize distinct subgroups, their biological impact and clinical significance as prognostic indicators remain to be defined. The tumor suppressor candidate-3 (TUSC3/N33) locates to a genomic region frequently deleted or silenced in cancers. TUSC3 is a subunit of the oligosaccharyltransferase (OST) complex at the endoplasmic reticulum (ER) which catalyzes bulk N-glycosylation of membrane and secretory proteins. However, the consequences of TUSC3 loss are largely unknown. Thus, the aim of the study was to characterize the functional and clinical relevance of TUSC3 expression in CRC patients' tissues (n=306 cases) and cell lines. TUSC3 mRNA expression was silenced by promoter methylation in 85 % of benign adenomas (n=46 cases) and 35 % of CRCs (n =74 cases). Epidermal growth factor receptor (EGFR) was selected as one exemplary ER-derived target protein of TUSC3-mediated posttranslational modification. We found that TUSC3 inhibited EGFR-signaling and promoted apoptosis in human CRC cells, whereas TUSC3 siRNA knock-down increased EGFR-signaling. Accordingly, in stage I/II node negative CRC patients (n=156 cases) loss of TUSC3 protein expression was associated with poor overall survival. In sum, our data suggested that epigenetic silencing of TUSC3 may be useful as a molecular marker for progression of early CRC.

Myotubularin-related protein 7 inhibits insulin signaling in colorectal cancer.

Phosphoinositide (PIP) phosphatases such as myotubularins (MTMs) inhibit growth factor receptor signaling. However, the function of myotubularin-related protein 7 (MTMR7) in cancer is unknown. We show that MTMR7 protein was down-regulated with increasing tumor grade (G), size (T) and stage (UICC) in patients with colorectal cancer (CRC) (n=1786). The presence of MTMR7 in the stroma correlated with poor prognosis, whereas MTMR7 expression in the tumor was not predictive for patients' survival. Insulin reduced MTMR7 protein levels in human CRC cell lines, and CRC patients with type 2 diabetes mellitus (T2DM) or loss of imprinting (LOI) of insulin-like growth factor 2 (IGF2) had an increased risk for MTMR7 loss. Mechanistically, MTMR7 lowered PIPs and inhibited insulin-mediated AKT-ERK1/2 signaling and proliferation in human CRC cell lines. MTMR7 provides a novel link between growth factor signaling and cancer, and may thus constitute a potential marker or drug target for human CRC.

Subcellular compartmentalization of docking protein-1 contributes to progression in colorectal cancer.

Full-length (FL) docking protein-1 (DOK1) is an adapter protein which inhibits growth factor and immune response pathways in normal tissues, but is frequently lost in human cancers. Small DOK1 variants remain in cells of solid tumors and leukemias, albeit, their functions are elusive. To assess the so far unknown role of DOK1 in colorectal cancer (CRC), we generated DOK1 mutants which mimic the domain structure and subcellular distribution of DOK1 protein variants in leukemia patients. We found that cytoplasmic DOK1 activated peroxisome-proliferator-activated-receptor-gamma (PPARγ) resulting in inhibition of the c-FOS promoter and cell proliferation, whereas nuclear DOK1 was inactive. PPARγ-agonist increased expression of endogenous DOK1 and interaction with PPARγ. Forward translation of this cell-based signaling model predicted compartmentalization of DOK1 in patients. In a large series of CRC patients, loss of DOK1 protein was associated with poor prognosis at early tumor stages (*p=0.001; n=1492). In tumors with cytoplasmic expression of DOK1, survival was improved, whereas nuclear localization of DOK1 correlated with poor outcome, indicating that compartmentalization of DOK1 is critical for CRC progression. Thus, DOK1 was identified as a prognostic factor for non-metastatic CRC, and, via its drugability by PPARγ-agonist, may constitute a potential target for future cancer treatments.