Cancer-Associated Fibroblasts and Desmoplastic Reactions Related to Cancer Invasiveness in Patients With Colorectal Cancer

Prognostic impact of tumor‑associated stroma in triple-negative breast cancer

AIM

To establish the histological categorization of tumor‑associated stroma (TAS) that reflects the biological behavior of triple-negative breast cancer (TNBC).

METHODS AND RESULTS

One-hundred-and-twenty surgically resected cases of TNBC were examined. We histologically categorized the TAS in the invasive frontal region into two groups: mature stroma (MS) and immature stroma (IS). The designation of IS was applied for tumors in which the largest myxoid stroma filled a high-power magnification field. When there were no myxoid stroma that meet the criteria for IS, TAS was categorized as MS. The tumors with type MS were observed in 103 (85.8%) of patients, whereas 17 (14.2%) of patients had tumors with IS. In total, 72 out of 120 patients with TNBC exhibited high tumor-infiltrating lymphocytes (TILs) representing 60% of the cohort. The incidences of high TILs were 66% (68 out of 103) in the MS group but only 23.5% (4 of 17) in the IS group (p = 0.001). Progression-free survival (PFS) and overall survival (OS) curves were different between IS and MS groups (p < 0.001 each), and Cox multivariate regression analysis revealed that IS was an independent indicator for lower PFS and OS rates (p < 0.001; p = 0.008).

CONCLUSION

Our findings suggest that TAS characteristics, particularly the distinction between IS and MS, play a significant role in the prognosis of TNBC. The presence of IS, associated with poor prognosis and low TILs, contrasts with the favorable outcomes observed in cases with MS. Understanding these TAS dynamics could aid in identifying patients with varying prognostic outcomes in TNBC, necessitating further research into the mechanisms behind these observations.

High-performance CT features supporting accurate pre-operative tumor staging in colon cancer

Background and aims

Accurate pre-treatment tumor staging is essential for treatment decision-making. Multi-slice spiral computed tomography (CT) is currently the standard method for pre-operative clinical tumor staging, but accurately applying the CT findings in tumor staging remains a challenge due to the poor pathological understanding of the CT signs. We aimed to pathologically interpret the key CT findings in order to identify reliable markers for pre-treatment staging of colon cancer.

Patients and methods

The following CT features from 136 colon adenocarcinomas were analyzed: colon wall pliability, outline contour, pericolic fat attenuations and vascularity, tumor fusion with adjacent organs, ascites, tumor size, and relevance between tumor and retroperitoneal fascia. These CT features were corroborated with histopathological findings. The diagnostic performance of these was further analyzed.

Results

Based on the postoperative pathological tumor staging (pT), 136 colon adenocarcinomas were classified into four stages: pT1 (n = 5), pT2 (n = 7), pT3 (n = 96), and pT4 (n = 28). Key findings include the following: (1) soft colon wall is a characteristic of the pT1 tumors, whereas stiff colon wall is a characteristic of the pT2~pT4 tumors; pathologically, stiff colon wall reflects the infiltration of tumor cells with desmoplastic reaction (DR) in muscularis propria; (2) small protuberances may help exclude the pT2 tumors. Histopathologically, small protuberances in pT2 cancer represent the pure DR on the surface of lamina propria, whereas the small protuberances in pT3~pT4 cancers represent the sub-serosal or extra-serosal cancer cell foci enwrapped by DR; (3) the presence of large protuberances, extensive reticulonodular fat stranding, and fusion with surrounding organs and ascites are diagnostic of pT4 tumors; and (4) the presence of extra-fascial nodules/streaks on CT scan could accurately diagnose the ascending/descending colon cancer of pT4 stage. Histologically, the presence of the above five CT features (large protuberances, extensive reticulonodular fat stranding, fusion with surrounding organs, ascites, and extra-fascial nodules/streaks) reflect the farther and deeper infiltration of tumor cells in serosa or retroperitoneal fascia involvement.

Conclusion

Our studies have identified multiple CT features that are practically useful in identifying and differentiating different stages of colon cancer prior to surgical procedures. These high-performance markers will provide valuable insights to the clinicians in making appropriate decisions in the management of patients with colon cancer.

Desmoplastic reaction in the microenvironment of head and neck and other solid tumors: the therapeutic barrier

Head and neck squamous cell carcinoma (HNSCC) remains a challenge due to limited prognostic biomarkers and therapeutic options. The tumor microenvironment (TME), particularly the desmoplastic reaction (DR) characterized by stromal fibrosis, plays a crucial role in cancer progression and resistance to therapy. This review aims to summarize the biological significance of DR in HNSCC initiation, progression, and treatment resistance. Histologically, DR in HNSCC correlates with invasion patterns and clinical outcomes, affecting disease-free and overall survival. The interaction between cancer-associated fibroblasts (CAFs) and TME influences immune responses, including resistance to immunotherapy. Notably, human papillomavirus-driven HNSCC exhibits distinct DR characteristics that further influence the prognosis. DR promotes epithelial-mesenchymal transition and cancer cell invasion through CAF-mediated extracellular matrix remodeling and signaling pathways such as transforming growth factor-beta. DR also affects bone invasion and chemotherapy resistance by modulating stromal responses. Therapeutic strategies targeting DR and stromal components show promise in overcoming therapeutic resistance including resistance to immune checkpoint inhibitors. Understanding the role of DR in HNSCC biology and its impact on treatment response is critical to developing effective therapeutic interventions.

Unravelling the difference of immune microenvironment characteristics between esophageal basaloid squamous cell carcinoma and conventional esophageal squamous cell carcinoma

OBJECTIVES

Esophageal basaloid squamous cell carcinoma (basaloid ESCC) is an uncommon variant of esophageal squamous cell carcinoma (ESCC). We characterized the tumor immune microenvironment features of basaloid ESCC, and compared them with conventional ESCC.

METHODS AND RESULTS

One hundred and four basaloid ESCC patients and 55 conventional ESCC patients were included in Cohort 1. Among 104 basaloid ESCC, 81 were pure basaloid ESCC, and 23 were mixed basaloid ESCC with invasive basaloid ESCC components and ESCC components. In pure basaloid ESCC, there were more immature desmoplastic reaction (P < 0.001), fewer peritumoral tertiary lymphoid structures (TLSs) (P < 0.001), and lower tumor proportional score (TPS) and combined positive score (CPS) (P < 0.001 and P = 0.004) than in conventional ESCC. In mixed basaloid ESCC, the number of mature or intermediate desmoplastic reaction (P < 0.001), the tumor-infiltrating lymphocytes (TILs) score (P = 0.043), the proportion of stromal CD8+ TILs (P = 0.047), the number of intratumoral CD20+ TILs (P < 0.001), the number of peritumoral TLSs (P = 0.001), the number of peritumoral matureTLSs (P = 0.021), and the PD-L1 (22C3) CPS (P = 0.016) were lower in the basaloid ESCC components than in the conventional ESCC components. In addition, the data of 141 ESCC patients with neoadjuvant chemoimmunotherapy (nICT) were collected to compare immunotherapeutic outcomes. Among 141 nICT-treated patients, 115 patients had residual tumor cells remaining, including 101 with conventional ESCC and 11 with basaloid ESCC. In basaloid ESCC, 18.2% patients had less than 10% residual viable tumor in the esophageal wall (effective response), which was lower than 58.6% in conventional ESCC (P = 0.025).

CONCLUSIONS

Our data indicated that basaloid ESCC had less benefits from immunotherapy than conventional ESCC, and manifested as immune "cold" with immature-type desmoplastic reaction, lower TILs, lower peritumoral TLSs, and lower PD-L1 expression than conventional ESCC.

Revolutionizing Cancer Treatment: Harnessing the Power of Mesenchymal Stem Cells for Precise Targeted Therapy in the Tumor Microenvironment

In recent years, mesenchymal stem cells (MSCs) have emerged as promising anti-- cancer mediators with the potential to treat several cancers. MSCs have been modified to produce anti-proliferative, pro-apoptotic, and anti-angiogenic molecules that could be effective against a variety of malignancies. Additionally, customizing MSCs with cytokines that stimulate pro-tumorigenic immunity or using them as vehicles for traditional chemical molecules with anti-cancer characteristics. Even though the specific function of MSCs in tumors is still challenged, promising outcomes from preclinical investigations of MSC-based gene therapy for a variety of cancers inspire the beginning of clinical trials. In addition, the tumor microenvironment (TME) could have a substantial influence on normal tissue stem cells, which can affect the treatment outcomes. To overcome the complications of TME in cancer development, MSCs could provide some signs of hope for converting TME into unequivocal therapeutic tools. Hence, this review focuses on engineered MSCs (En-MSCs) as a promising approach to overcoming the complications of TME.

Early Onset Colorectal Cancer: Molecular Underpinnings Accelerating Occurrence

The onset of colorectal cancer (CRC) in patients younger than 50 continues to rapidly increase. This study highlights the epidemiologic changes, risk factors, clinical characteristics, and molecular profiles prevalent in early onset CRC patients, and identifies key areas for future research. It has been noted that only a small fraction of early onset CRC cases is attributed to known hereditary mutations and fit the canonical pathway of late-onset colorectal cancer development. To highlight this, we review the genetic and epigenetic modifications specific to early onset CRC. We also discuss the synergetic effect of single-nucleotide polymorphisms and environmental factors on the early onset of CRC. Additionally, we discuss the potential of noninvasive biomarker assays to enhance early detection, screening, diagnosis, and prognostic outcome predictions.

Improving tumor microenvironment assessment in chip systems through next-generation technology integration

The tumor microenvironment (TME) comprises a diverse array of cells, both cancerous and non-cancerous, including stromal cells and immune cells. Complex interactions among these cells play a central role in driving cancer progression, impacting critical aspects such as tumor initiation, growth, invasion, response to therapy, and the development of drug resistance. While targeting the TME has emerged as a promising therapeutic strategy, there is a critical need for innovative approaches that accurately replicate its complex cellular and non-cellular interactions; the goal being to develop targeted, personalized therapies that can effectively elicit anti-cancer responses in patients. Microfluidic systems present notable advantages over conventional in vitro 2D co-culture models and in vivo animal models, as they more accurately mimic crucial features of the TME and enable precise, controlled examination of the dynamic interactions among multiple human cell types at any time point. Combining these models with next-generation technologies, such as bioprinting, single cell sequencing and real-time biosensing, is a crucial next step in the advancement of microfluidic models. This review aims to emphasize the importance of this integrated approach to further our understanding of the TME by showcasing current microfluidic model systems that integrate next-generation technologies to dissect cellular intra-tumoral interactions across different tumor types. Carefully unraveling the complexity of the TME by leveraging next generation technologies will be pivotal for developing targeted therapies that can effectively enhance robust anti-tumoral responses in patients and address the limitations of current treatment modalities.

Hallmarks of perineural invasion in pancreatic ductal adenocarcinoma: new biological dimensions

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant tumor with a high metastatic potential. Perineural invasion (PNI) occurs in the early stages of PDAC with a high incidence rate and is directly associated with a poor prognosis. It involves close interaction among PDAC cells, nerves and the tumor microenvironment. In this review, we detailed discuss PNI-related pain, six specific steps of PNI, and treatment of PDAC with PNI and emphasize the importance of novel technologies for further investigation.

Characterisation of colorectal cancer by hierarchical clustering analyses for five stroma-related markers

Evidence for the tumour-supporting capacities of the tumour stroma has accumulated rapidly in colorectal cancer (CRC). Tumour stroma is composed of heterogeneous cells and components including cancer-associated fibroblasts (CAFs), small vessels, immune cells, and extracellular matrix proteins. The present study examined the characteristics of CAFs and collagen, major components of cancer stroma, by immunohistochemistry and Sirius red staining. The expression status of five independent CAF-related or stromal markers, decorin (DCN), fibroblast activation protein (FAP), podoplanin (PDPN), alpha-smooth muscle actin (ACTA2), and collagen, and their association with clinicopathological features and clinical outcomes were analysed. Patients with DCN-high tumours had a significantly worse 5-year survival rate (57.3% versus 79.0%; p = 0.044). Furthermore, hierarchical clustering analyses for these five markers identified three groups that showed specific characteristics: a solid group (cancer cell-rich, DCNLowPDPNLow); a PDPN-dominant group (DCNMidPDPNHigh); and a DCN-dominant group (DCNHighPDPNLow), with a significant association with patient survival (p = 0.0085). Cox proportional hazards model identified the PDPN-dominant group (hazard ratio = 0.50, 95% CI = 0.26-0.96, p = 0.037) as a potential favourable factor compared with the DCN-dominant group. Of note, DCN-dominant tumours showed the most advanced pT stage and contained the lowest number of CD8+ and FOXP3+ immune cells. This study has revealed that immunohistochemistry and special staining of five stromal factors with hierarchical clustering analyses could be used for the prognostication of patients with CRC. Cancer stroma-targeting therapies may be candidate treatments for patients with CRC.

Correlation analysis of interstitial maturity and prognosis of colorectal cancer: Meta-analysis

BACKGROUND

To investigate the relationship between interstitial maturity and prognosis of colorectal cancer.

AIM

To examine the correlation between interstitial maturity and the prognosis of colorectal cancer.

METHODS

The paper database PubMed, EMBASE, Cochranelibrary, Springerlink, CNKI, and Wanfang database were searched until December 2023. "tumor stroma maturity" "desmoplastic stroma reaction" "desmoplastic reaction" "stroma reaction" "degree of stroma reaction "" stroma classification" "stroma density" "colorectal cancer" "colon cancer" "rectal cancer" "prognosis" were searched for the search terms. Two system assessors independently screened the literature quality according to the inclusion exclusion criteria, Quality evaluation and data extraction were performed for the included literatures, and meta-analysis was performed for randomized control trials included at using Review Manager 5.2 software.

RESULTS

Finally, data of 9849 patients with colorectal cancer from 19 cosets in 15 literatures were included, including 4339 patients with mature type (control group), 3048 patients with intermediate type (intermediate group) and 2456 patients with immature type (immature group). The results of meta-analysis showed: Relapse-free survival [hazard ratio (HR) = 2.66, 95% confidence interval (CI): 2.30-3.08; P < 0.00001], disease-free survival (HR = 3.68, 95%CI: 2.33-5.81; P < 0.00001) and overall survival (HR = 1.70, 95%CI: 1.53-1.87; P < 0.00001) were significantly lower than those in mature group (control group); relapse-free survival (HR = 1.36, 95%CI: 1.17-1.59; P < 0.0001) and disease-free survival rate (HR = 1.85, 95%CI: 1.53-2.24; P < 0.0001) was significantly lower than the mature group (control group).

CONCLUSION

There is the correlation between tumor interstitial maturity and survival prognosis of colorectal cancer, and different degrees of tumor interstitial maturity have a certain impact on the quality of life of colorectal cancer patients.

Diagnostic and prognostic significance of keloid-like collagen remodeling patterns in the extracellular matrix of colorectal cancer

Background

The desmoplastic reaction is considered a promising prognostic parameter for colorectal cancer. However, intermediate desmoplastic reaction is characterized by sizeable stromal heterogeneity, including both small amounts of keloid-like collagen (KC) in the fibrotic stroma and thick tufts of KC circumferentially surrounding cancer nests and occupying most of the fields of view. The present study aimed to evaluate the diagnostic and prognostic significance of KC histophenotyping with a quantitative visual assessment of its presence in the stroma of the invasive margin of TNM (The "tumor-node-metastasis" classification) stage II/III colorectal cancer (CRC).

Methods and results

175 resected tumors from patients with TNM stage II/III CRC were examined. Keloid-like collagen was assessed according to Ueno H. criteria. KC was assessed at the primary tumor invasive margin using Hematoxylin & Eosin and Masson's trichrome staining. The cut-off point for KC was examined using "the best cutoff approach by log-rank test." Using a cutoff point of 30%, we histologically divided fibrous stroma in the invasive area into two groups: "type A"-KC ≤ 0.3 and "type B"-KC>0.3. Type A stroma was observed in 48% of patients, type B-in 52%. The association between collagen amount and 5-year recurrence-free survival (5-RFS) was assessed using Cox regression analysis. Kaplan-Meier analysis and log-rank tests were used to assess the significance of survival analysis. Analysis of categorical variables showed that increased KC in CRC stroma predicted adverse outcomes for 5-RFS (hazard ratio [HR] = 3.143, 95%, confidence interval [CI] = 1.643-6.012, p = 0.001). Moreover, in Kaplan-Meier analysis, the log-rank test showed that type B exhibited worse 5-RFS than type A (p = 0.000).

Conclusion

KC is an independent predictor of 5-year overall and RFS in patients with TNM stage II/III CRC treated with surgery, with worse survival rates when the amount of KC increases by >30%.

Biophysical perspectives to understanding cancer-associated fibroblasts

The understanding of cancer has evolved significantly, with the tumor microenvironment (TME) now recognized as a critical factor influencing the onset and progression of the disease. This broader perspective challenges the traditional view that cancer is primarily caused by mutations, instead emphasizing the dynamic interaction between different cell types and physicochemical factors within the TME. Among these factors, cancer-associated fibroblasts (CAFs) command attention for their profound influence on tumor behavior and patient prognoses. Despite their recognized importance, the biophysical and mechanical interactions of CAFs within the TME remain elusive. This review examines the distinctive physical characteristics of CAFs, their morphological attributes, and mechanical interactions within the TME. We discuss the impact of mechanotransduction on CAF function and highlight how these cells communicate mechanically with neighboring cancer cells, thereby shaping the path of tumor development and progression. By concentrating on the biomechanical regulation of CAFs, this review aims to deepen our understanding of their role in the TME and to illuminate new biomechanical-based therapeutic strategies.

Exosomes-Promising Carriers for Regulatory Therapy in Oncology

Extracellular vesicles (EVs), including exosomes and microvesicles, together with apoptotic bodies form a diverse group of nanoparticles that play a crucial role in intercellular communication, participate in numerous physiological and pathological processes. In the context of cancer, they can allow the transfer of bioactive molecules and genetic material between cancer cells and the surrounding stromal cells, thus promoting such processes as angiogenesis, metastasis, and immune evasion. In this article, we review recent advances in understanding how EVs, especially exosomes, influence tumor progression and modulation of the microenvironment. The key mechanisms include exosomes inducing the epithelial-mesenchymal transition, polarizing macrophages toward protumoral phenotypes, and suppressing antitumor immunity. The therapeutic potential of engineered exosomes is highlighted, including their loading with drugs, RNA therapeutics, or tumor antigens to alter the tumor microenvironment. Current techniques for their isolation, characterization, and engineering are discussed. Ongoing challenges include improving exosome loading efficiency, optimizing biodistribution, and enhancing selective cell targeting. Overall, exosomes present promising opportunities to understand tumorigenesis and develop more targeted diagnostic and therapeutic strategies by exploiting the natural intercellular communication networks in tumors. In the context of oncology, regulatory therapy provides the possibility of reproducing the original conditions that are unfavorable for the existence of the cancer process and may thus be a feasible alternative to population treatments. We also review current access to the technology enabling regulatory intervention in the cancer process using exosomes.

Simultaneous Expression of CD70 and POSTN in Cancer-Associated Fibroblasts Predicts Worse Survival of Colorectal Cancer Patients

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide, with high morbidity and mortality rates. The evidence for the tumor-supporting capacities of cancer-associated fibroblasts (CAFs) that modulate cancer cell proliferation, invasion, metastasis, and tumor immunity, including in CRC, has been attracting attention. The present study examined the expression status of CD70 and POSTN in CRC and analyzed their association with clinicopathological features and clinical outcomes. In the present study, in total 15% (40/269) and 44% (119/269) of cases exhibited CD70 and POSTN expression on CAFs, respectively. Co-expression of CD70 and POSTN was detected in 8% (21/269) of patients. Fluorescent immunohistochemistry identified the co-expression of CD70 and POSTN with FAP and PDPN, respectively. ACTA2 was not co-expressed with CD70 or POSTN in CRC CAFs. CRC with CD70+/POSTN+ status in CAFs was significantly associated with distant organ metastasis (p = 0.0020) or incomplete resection status (p = 0.0011). CD70+/POSTN+ status tended to associate with advanced pT stage (p = 0.032) or peritoneal metastasis (p = 0.0059). Multivariate Cox hazards regression analysis identified CD70+/POSTN+ status in CAFs [hazard ratio (HR) = 3.78] as a potential independent risk factor. In vitro experiments revealed the activated phenotypes of colonic fibroblasts induced by CD70 and POSTN, while migration and invasion assays identified enhanced migration and invasion of CRC cells co-cultured with CD70- and POSTN-expressing colonic fibroblasts. On the basis of our observations, CD70 and POSTN immunohistochemistry can be used in the prognostication of CRC patients. CRC CAFs may be a promising target in the treatment of CRC patients.

The Impact of Cancer-Associated Fibroblasts on the Biology and Progression of Colorectal Carcinomas

(1) Colorectal cancer (CRC) is a leading cause of cancer-related deaths globally. Cancer-associated fibroblasts (CAFs) are major components of CRC's tumour microenvironment (TME), but their biological background and interplay with the TME remain poorly understood. This study investigates CAF biology and its impact on CRC progression. (2) The cohort comprises 155 cases, including CRC, with diverse localizations, adenomas, inflammations, and controls. Digital gene expression analysis examines genes associated with signalling pathways (MAPK, PI3K/Akt, TGF-β, WNT, p53), while next-generation sequencing (NGS) determines CRC mutational profiles. Immunohistochemical FAP scoring assesses CAF density and activity. (3) FAP expression is found in 81 of 150 samples, prevalent in CRC (98.4%), adenomas (27.5%), and inflammatory disease (38.9%). Several key genes show significant associations with FAP-positive fibroblasts. Gene set enrichment analysis (GSEA) highlights PI3K and MAPK pathway enrichment alongside the activation of immune response pathways like natural killer (NK)-cell-mediated cytotoxicity via CAFs. (4) The findings suggest an interplay between CAFs and cancer cells, influencing growth, invasiveness, angiogenesis, and immunogenicity. Notably, TGF-β, CDKs, and the Wnt pathway are affected. In conclusion, CAFs play a significant role in CRC and impact the TME throughout development.

Prognostic significance of tumor budding in patients with pancreatic invasive ductal carcinoma who received neoadjuvant therapy

Neoadjuvant therapy is commonly used for invasive pancreatic ductal carcinoma (PDAC). Tumor budding and high podoplanin expression in cancer-associated fibroblasts (CAFs) are prognostic factors in patients with various carcinomas including PDAC who have not received neoadjuvant therapy. In this study, we investigated whether tumor budding and podoplanin-positive CAFs are associated with outcomes in Japanese PDAC patients with neoadjuvant therapy. Histopathological findings of surgically resected PDACs with neoadjuvant therapy from 2005 to 2018 were reviewed (n = 97). With reference to International Tumor Budding Consensus Conference recommendations, tumors were evaluated for budding at 20 × magnification (/0.785 mm2) and at 40 × magnification (/0.237 mm2; mean number of fields: 3) for podoplanin expression in CAFs (%). Overall survival, disease-free survival, and disease-specific survival (DSS) were analyzed using the log-rank test and Cox proportional hazards model. After adjusting for T category, N category, resection margin, and adjuvant therapy, multivariate analyses demonstrated that tumor budding at 40 × magnification was an independent prognostic factor for worse DSS (hazard ratio: 2.41, p = 0.022). Tumor budding at 20 × magnification and podoplanin-positive CAFs tended to be associated with worse DSS; however, these findings were not statistically significant. Our findings indicate that tumor budding is an independent prognostic factor in PDAC patients with neoadjuvant therapy.

The nerve cells in gastrointestinal cancers: from molecular mechanisms to clinical intervention

Gastrointestinal (GI) cancer is a formidable malignancy with significant morbidity and mortality rates. Recent studies have shed light on the complex interplay between the nervous system and the GI system, influencing various aspects of GI tumorigenesis, such as the malignance of cancer cells, the conformation of tumor microenvironment (TME), and the resistance to chemotherapies. The discussion in this review first focused on exploring the intricate details of the biological function of the nervous system in the development of the GI tract and the progression of tumors within it. Meanwhile, the cancer cell-originated feedback regulation on the nervous system is revealed to play a crucial role in the growth and development of nerve cells within tumor tissues. This interaction is vital for understanding the complex relationship between the nervous system and GI oncogenesis. Additionally, the study identified various components within the TME that possess a significant influence on the occurrence and progression of GI cancer, including microbiota, immune cells, and fibroblasts. Moreover, we highlighted the transformation relationship between non-neuronal cells and neuronal cells during GI cancer progression, inspiring the development of strategies for nervous system-guided anti-tumor drugs. By further elucidating the deep mechanism of various neuroregulatory signals and neuronal intervention, we underlined the potential of these targeted drugs translating into effective therapies for GI cancer treatment. In summary, this review provides an overview of the mechanisms of neuromodulation and explores potential therapeutic opportunities, providing insights into the understanding and management of GI cancers.

A Vaccine against Cancer: Can There Be a Possible Strategy to Face the Challenge? Possible Targets and Paradoxical Effects

Is it possible to have an available vaccine that eradicates cancer? Starting from this question, this article tries to verify the state of the art, proposing a different approach to the issue. The variety of cancers and different and often unknown causes of cancer impede, except in some cited cases, the creation of a classical vaccine directed at the causative agent. The efforts of the scientific community are oriented toward stimulating the immune systems of patients, thereby preventing immune evasion, and heightening chemotherapeutic agents effects against cancer. However, the results are not decisive, because without any warning signs, metastasis often occurs. The purpose of this paper is to elaborate on a vaccine that must be administered to a patient in order to prevent metastasis; metastasis is an event that leads to death, and thus, preventing it could transform cancer into a chronic disease. We underline the fact that the field has not been studied in depth, and that the complexity of metastatic processes should not be underestimated. Then, with the aim of identifying the target of a cancer vaccine, we draw attention to the presence of the paradoxical actions of different mechanisms, pathways, molecules, and immune and non-immune cells characteristic of the tumor microenvironment at the primary site and pre-metastatic niche in order to exclude possible vaccine candidates that have opposite effects/behaviors; after a meticulous evaluation, we propose possible targets to develop a metastasis-targeting vaccine. We conclude that a change in the current concept of a cancer vaccine is needed, and the efforts of the scientific community should be redirected toward a metastasis-targeting vaccine, with the increasing hope of eradicating cancer.

Prognostic Significance of Tumour Budding and Desmoplastic Reaction in Intestinal-Type Gastric Adenocarcinoma

Objective. Tumour budding and desmoplastic reactions in peritumoural stroma are features of the tumour microenvironment that are associated with colorectal cancer prognosis but have not been as thoroughly examined in gastric cancer. We aimed to further characterize the prognostic role of tumour budding and desmoplastic reaction in gastric adenocarcinoma with intestinal differentiation. Methods. 76 curative gastrectomy specimens were identified, excluding post-neoadjuvant cases or cases with >50% diffuse-type histology. Tumour budding was defined and graded according to the International Tumor Budding Consensus Conference recommendations and desmoplastic reaction was classified as described by Ueno et al 2017. Tumour budding and desmoplastic reaction were analyzed for associations with pathologic features and clinical outcomes. Results. Tumour budding was associated with pT (P < .001), pN (P < .004), overall stage (P < .001), LVI (P < .001) and PNI (P = .002). Desmoplastic reaction was associated with pT (P < .001), pN (P = .005), overall stage (P = .031) and PNI (P < .001), but not LVI. Survival analysis showed decreased overall survival (OS) and recurrence-free survival (RFS) for intermediate and high grade tumour budding (P = .031, .014 respectively). Immature stroma was significantly associated with RFS but not OS. Neither tumour budding nor desmoplastic reaction were independent predictors of OS or RFS on multivariate analysis in this cohort. Conclusion. Tumour budding and desmoplastic reaction were associated with known pathologic risk factors. Prognostically, tumour budding was associated with OS and RFS while desmoplastic reaction was associated with RFS only. Our data suggest that tumour budding and desmoplastic reaction have prognostic value in intestinal-type gastric adenocarcinoma.

Prognostic evaluation of cancer associated fibrosis and tumor budding in colorectal cancer

Colorectal carcinoma (CRC) is the second most common cancer and third leading cause of cancer-related deaths worldwide. Although the staging system provides a standardized guidance in treatment regimens, the clinical outcome in patients with colon cancer at the same TNM stage may vary dramatically. Thus, for better predictive accuracy, further prognostic and/or predictive markers are required. Patients who underwent curative surgery for colorectal cancer in past 3 years at a tertiary care hospital were retrospectively included in this cohort study to evaluate the prognostic indicators, tumor-stroma ratio (TSR) and tumor budding (TB) on histopathological sections and correlated them with pTNM staging, histopathological grading, tumor size, and lymphovascular and perineural invasion in patients with colo-rectal cancer. TB was strongly associated with advanced stage of the disease along with lympho-vascular and peri-neural invasion and it can be used as an independent adverse prognostic factor. TSR showed a better sensitivity, specificity, PPV and NPV as compared to TB in patients having poorly differentiated adenocarcinoma than those with moderately or well differentiated.

Type 1 and type 2 cytokine-mediated immune orchestration in the tumour microenvironment and their therapeutic potential

Cancer remains the second leading cause of death worldwide despite modern breakthroughs in medicine, and novel treatments are urgently needed. The revolutionary success of immune checkpoint inhibitors in the past decade serves as proof of concept that the immune system can be effectively harnessed to treat cancer. Cytokines are small signalling proteins with critical roles in orchestrating the immune response and have become an attractive target for immunotherapy. Type 1 immune cytokines, including interferon γ (IFNγ), interleukin-12 (IL-12), and tumour necrosis factor α (TNFα), have been shown to have largely tumour suppressive roles in part through orchestrating anti-tumour immune responses mediated by natural killer (NK) cells, CD8⁺ T cells and T helper 1 (Th1) cells. Conversely, type 2 immunity involving group 2 innate lymphoid cells (ILC2s) and Th2 cells are involved in tissue regeneration and wound repair and are traditionally thought to have pro-tumoural effects. However, it is found that the classical type 2 immune cytokines IL-4, IL-5, IL-9, and IL-13 may have conflicting roles in cancer. Similarly, type 2 immunity-related cytokines IL-25 and IL-33 with recently characterised roles in cancer may either promote or suppress tumorigenesis in a context-dependent manner. Furthermore, type 1 cytokines IFNγ and TNFα have also been found to have pro-tumoural effects under certain circumstances, further complicating the overall picture. Therefore, the dichotomy of type 1 and type 2 cytokines inhibiting and promoting tumours respectively is not concrete, and attempts of utilising these for cancer immunotherapy must take into account all available evidence. This review provides an overview summarising the current understanding of type 1 and type 2 cytokines in tumour immunity and discusses the prospects of harnessing these for immunotherapy in light of previous and ongoing clinical trials.

Tumor budding as a potential prognostic marker in determining the behavior of primary liver cancers

Hepatocellular (HCC) and intrahepatic cholangiocarcinoma (ICC), the most common primary tumors of the liver, are among the most important causes of cancer deaths worldwide. Because patients with primary liver tumors are frequently diagnosed at an advanced stage and have high mortality, many efforts have been made to identify new markers to determine their behavior and treatment, similar to those in other solid organ tumors. Recently, morphological assessment of tumor budding (TB) has been revealed as a promising prognostic finding to predict tumor behavior and survival across several different tumor types. Currently, the TB score in colorectal cancer has been revealed as an important parameter in pathology report protocols to determine the course of the disease. Regarding the liver, despite enormous data showing that many mechanisms involved in TB are associated with tumor behavior in both HCC and ICC, studies focusing on the role of TB in predicting the behavior and prognosis of these tumors have started to be investigated very recently. The purpose of this review is to present data about TB in primary tumors of the liver, pointing out the potential role of this parameter in determining the course of the disease, and emphasize the need to increase the number of further studies focusing on the evaluation of this parameter with an overview of the mechanisms involved in TB.

Antibody-Loaded Nanoplatforms for Colorectal Cancer Diagnosis and Treatment: An Update

At present, colorectal cancer (CRC) is the second deadliest type of cancer, partly because a high percentage of cases are diagnosed at advanced stages when tumors have already metastasized. Thus, there is an urgent need to develop novel diagnostic systems that allow early detection as well as new therapeutic systems that are more specific than those currently available. In this context, nanotechnology plays a very important role in the development of targeted platforms. In recent decades, many types of nanomaterials with advantageous properties have been used for nano-oncology applications and have been loaded with different types of targeted agents, capable of recognizing tumor cells or biomarkers. Indeed, among the different types of targeted agents, the most widely used are monoclonal antibodies, as the administration of many of them is already approved by the main drug regulatory agencies for the treatment of several types of cancer, including CRC. In this way, this review comprehensively discusses the main drawbacks of the conventional screening technologies and treatment for CRC, and it presents recent advances in the application of antibody-loaded nanoplatforms for CRC detection, therapy or theranostics applications.

Important Cells and Factors from Tumor Microenvironment Participated in Perineural Invasion

Perineural invasion (PNI) as the fourth way for solid tumors metastasis and invasion has attracted a lot of attention, recent research reported a new point that PNI starts to include axon growth and possible nerve "invasion" to tumors as the component. More and more tumor-nerve crosstalk has been explored to explain the internal mechanism for tumor microenvironment (TME) of some types of tumors tends to observe nerve infiltration. As is well known, the interaction of tumor cells, peripheral blood vessels, extracellular matrix, other non-malignant cells, and signal molecules in TME plays a key role in the occurrence, development, and metastasis of cancer, as to the occurrence and development of PNI. We aim to summarize the current theories on the molecular mediators and pathogenesis of PNI, add the latest scientific research progress, and explore the use of single-cell spatial transcriptomics in this invasion way. A better understanding of PNI may help to understand tumor metastasis and recurrence and will be beneficial for improving staging strategies, new treatment methods, and even paradigm shifts in our treatment of patients.

Engineering chimeric antigen receptor T cells for solid tumour therapy

Cell-based immunotherapy, for example, chimeric antigen receptor T (CAR-T) cell immunotherapy, has revolutionized cancer treatment, particularly for blood cancers. However, factors such as insufficient T cell tracking, tumour heterogeneity, inhibitory tumour microenvironment (TME) and T cell exhaustion limit the broad application of CAR-based immunotherapy for solid tumours. In particular, the TME is a complex and evolving entity, which is composed of cells of different types (e.g., cancer cells, immune cells and stromal cells), vasculature, soluble factors and extracellular matrix (ECM), with each component playing a critical role in CAR-T immunotherapy. Thus, developing approaches to mitigate the inhibitory TME factors is critical for future success in applying CAR-T cells for solid tumour treatment. Accordingly, understanding the bilateral interaction of CAR-T cells with the TME is in pressing need to pave the way for more efficient therapeutics. In the following review, we will discuss TME-associated aspects with an emphasis on T cell trafficking, ECM barriers, abnormal vasculature, solid tumour heterogenicity and immune suppressive microenvironment. We will then summarize current engineering strategies to overcome the challenges posed by the TME-associated factors. Lastly, the future directions for engineering efficient CAR-T cells for solid tumour therapy will be discussed.

FSP-1 expression in cancer cells is relevant to long-term oncological outcomes in nonmetastatic colorectal cancer

Purpose

Recent studies have revealed that the expression of cancer-associated fibroblast (CAF) activation biomarkers in cancer cells is associated with clinical outcomes in patients with certain types of malignant tumors. However, whether the expression of CAF activation biomarkers affects the prognosis of colorectal cancer (CRC) has not been fully elucidated. This study aimed to evaluate the association between the expression of CAF activation biomarkers in cancer cells with cancer invasion and long-term oncological outcomes in patients with CRC.

Methods

Cancer specimens obtained from 135 patients with stage I-III CRC were examined using immunohistochemical staining to evaluate the expression of fibroblast specific protein-1 (FSP-1), fibroblast activation protein α (FAPα), α-smooth muscle actin (α-SMA), and vimentin in cancer cells.

Results

FSP-1 expression in cancer cells was significantly associated with lymphatic invasion, perineural invasion, tumor (T) status, and lymph node (N) status. FAPα expression in cancer cells was significantly associated with lymphatic invasion. On univariate and multivariate analyses, FSP-1 and α-SMA expression in cancer cells were associated with a short 10-year overall survival (OS) and high 10-year systemic recurrence (SR), respectively. Tumor budding was associated with a short 10-year OS. However, FAPα and vimentin did not contribute to the prognosis in this study.

Conclusion

In this study, we found that FSP-1 expression in cancer cells was related to cancer invasion. Additionally, FSP-1 and α-SMA expression in cancer cells was associated with 10-year OS and SR, respectively. Therefore, these markers may be used as predictors of long-term oncological outcomes in patients with CRC.

Emerging roles for IL-25 and IL-33 in colorectal cancer tumorigenesis

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide, and is largely refractory to current immunotherapeutic interventions. The lack of efficacy of existing cancer immunotherapies in CRC reflects the complex nature of the unique intestinal immune environment, which serves to maintain barrier integrity against pathogens and harmful environmental stimuli while sustaining host-microbe symbiosis during homeostasis. With their expression by barrier epithelial cells, the cytokines interleukin-25 (IL-25) and IL-33 play key roles in intestinal immune responses, and have been associated with inappropriate allergic reactions, autoimmune diseases and cancer pathology. Studies in the past decade have begun to uncover the important roles of IL-25 and IL-33 in shaping the CRC tumour immune microenvironment, where they may promote or inhibit tumorigenesis depending on the specific CRC subtype. Notably, both IL-25 and IL-33 have been shown to act on group 2 innate lymphoid cells (ILC2s), but can also stimulate an array of other innate and adaptive immune cell types. Though sometimes their functions can overlap they can also produce distinct phenotypes dependent on the differential distribution of their receptor expression. Furthermore, both IL-25 and IL-33 modulate pathways previously known to contribute to CRC tumorigenesis, including angiogenesis, tumour stemness, invasion and metastasis. Here, we review our current understanding of IL-25 and IL-33 in CRC tumorigenesis, with specific focus on dissecting their individual function in the context of distinct subtypes of CRC, and the potential prospects for targeting these pathways in CRC immunotherapy.

Evaluation of histopathological response to neoadjuvant therapy in rectal cancer using slide-free, stain-free multimodal multiphoton microscopy

Neoadjuvant therapy has become a standard treatment for patients with locally advanced rectal cancer to achieve better prognostic outcomes. The response to treatment has been shown to correlate closely with the prognosis. However, current evaluation systems only provide coarse assessment on limited information, due to the lack of accurate and reproducible approach for quantitation of different types of responses. In this study, a novel stain-free, slide-free multimodal multiphoton microscopy imaging technique was applied to image rectal cancer tissues after neoadjuvant therapies with high resolution and contrast. Qualitative and quantitative evaluation of tumor, stromal, and inflammatory responses were demonstrated which are consistent with current tumor regression grading system using American Joint Committee on Cancer criteria, showing the great potential of such approach to build a more informative grading system for accurate and standardizable assessment of neoadjuvant therapy in rectal cancer.

Construction and Verification of a Fibroblast-Related Prognostic Signature Model for Colon Cancer

Traditionally, cancer-associated fibroblasts (CAFs), an essential component of tumor microenvironment, were exert a crucial part in colon cancer progression. In this study, single-cell RNA-sequencing (scRNA-seq) data from 23 and bulk RNA-seq data from 452 colon cancer patients were extracted from the GEO database and TCGA-COAD and GEO databases, respectively. From single-cell analysis, 825 differentially expressed genes (DEGs) in CAFs were identified between each pair of six newly defined CAFs, named enCAF, adCAF, vaCAF, meCAF, erCAF, and cyCAF. Cell communication analysis with the iTALK package showed communication relationship between CAFs, including cell autocrine, cytokine, and growth factor subtypes, such as receptor-ligand pairs of TNFSF14-LTBR, IL6-F3, and IL6-IL6ST. Herein, we demonstrated the presence and prognostic value of adCAF and erCAF in colon cancer based on CIBERSORTx, combining single-cell marker genes and transcriptomics data. The prognostic significance of the enCAF and erCAF has been indirectly proved by both the correlation analysis with macrophages and CAFs, and the quantitative reverse transcription-polymerase chain reaction (qRT-PCR) experiment based on 20 paired tumor samples. A prognostic model was constructed with 10 DEGs using the LASSO Cox regression method. The model was validated using two testing datasets, indicate a significant survival accuracy (p < 0.0025). Correlation analyses between clinical information, such as age, gender, tumor stage and tumor features (tumor purity and immune score), and risk scores revealed our CAF-related model’s robustness and excellent performance. Cell infiltration analysis by xCell revealed that the interaction between CAFs and multiple non-specific immune cells such as macrophages and the dendritic cell was a vital factor affecting immune score and prognosis. Finally, we analyzed how common anti-cancer drugs, including camptothecin, docetaxel and bortezomib, and immunotherapy, such as anti-PD-1 treatment, could be different in low-risk and high-risk patients inferred from our CAF-related model. In conclusion, the study utilized refined colon cancer fibroblast subsets and established the prognostic effects from the interaction with nonspecific immune cell.

Intratumoral Budding in Pretreatment Biopsies, among Tumor Microenvironmental Components, Can Predict Prognosis and Neoadjuvant Therapy Response in Colorectal Adenocarcinoma

Background and Objectives: The prediction of the prognosis and effect of neoadjuvant therapy is vital for patients with advanced or unresectable colorectal carcinoma (CRC). Materials and Methods: We investigated several tumor microenvironment factors, such as intratumoral budding (ITB), desmoplastic reaction (DR), and Klintrup-Mäkinen (KM) inflammation grade, and the tumor-stroma ratio (TSR) in pretreatment biopsy samples (PBSs) collected from patients with advanced or unresectable CRC. A total of 85 patients with 74 rectal carcinomas and 11 colon cancers treated at our hospital were enrolled; 66 patients had curative surgery and 19 patients received palliative treatment. Results: High-grade ITB was associated with recurrence (p = 0.002), death (p = 0.034), and cancer-specific death (p = 0.034). Immature DR was associated with a higher grade of clinical tumor-node-metastasis stage (cTNM) (p = 0.045), cN category (p = 0.045), and cM category (p = 0.046). The KM grade and TSR were not related to any clinicopathological factors. High-grade ITB had a significant relationship with tumor regression in patients who received curative surgery (p = 0.049). Conclusions: High-grade ITB in PBSs is a potential unfavorable prognostic factor for patients with advanced CRC. Immature DR, TSR, and KM grade could not predict prognosis or therapy response in PBSs.

Molecular mechanisms of tumour budding and its association with microenvironment in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer worldwide. Poor survival of CRC associated with the development of tumour metastasis led to the investigation of the potential biomarkers to predict outcomes in CRC patients. Tumour budding (TB) is a well-known independent prognostic marker for poor survival and disease metastasis. Therefore, it has been suggested that TB status is included in routine clinicopathological factors for risk assessment in CRC. In contrast with a vast majority of studies regarding the prognostic power of TB, there is no clear evidence pertaining to the underlying molecular mechanism driving this phenotype, or an understanding of TB relationship with the tumour microenvironment (TME). The aim of the present study is to present a comprehensive review of TB and tumour cell signalling pathways together with the cross-talk of immune cells that could drive TB formation in CRC.

Mechanobiology of Colorectal Cancer

In this review, the mechanobiology of colorectal cancer (CRC) are discussed. Mechanotransduction of CRC is addressed considering the relationship of several biophysical cues and biochemical pathways. Mechanobiology is focused on considering how it may influence epithelial cells in terms of motility, morphometric changes, intravasation, circulation, extravasation, and metastization in CRC development. The roles of the tumor microenvironment, ECM, and stroma are also discussed, taking into account the influence of alterations and surface modifications on mechanical properties and their impact on epithelial cells and CRC progression. The role of cancer-associated fibroblasts and the impact of flow shear stress is addressed in terms of how it affects CRC metastization. Finally, some insights concerning how the knowledge of biophysical mechanisms may contribute to the development of new therapeutic strategies and targeting molecules and how mechanical changes of the microenvironment play a role in CRC disease are presented.

The Colorectal Cancer Tumor Microenvironment and Its Impact on Liver and Lung Metastasis

Simple Summary

Colorectal cancer (CRC) is the third most common cancer worldwide. Metastasis to secondary organs, such as the liver and lungs, is a key driver of CRC-related mortality. The tumor microenvironment, which consists of the primary cancer cells, as well as associated support and immune cells, significantly affects the behavior of CRC cells at the primary tumor site, as well as in metastatic lesions. In this paper, we review the role of the individual components of the tumor microenvironment on tumor progression, immune evasion, and metastasis, and we discuss the implications of these components on antitumor therapies.

Abstract

Colorectal cancer (CRC) is the third most common malignancy and the second most common cause of cancer-related mortality worldwide. A total of 20% of CRC patients present with distant metastases, most frequently to the liver and lung. In the primary tumor, as well as at each metastatic site, the cellular components of the tumor microenvironment (TME) contribute to tumor engraftment and metastasis. These include immune cells (macrophages, neutrophils, T lymphocytes, and dendritic cells) and stromal cells (cancer-associated fibroblasts and endothelial cells). In this review, we highlight how the TME influences tumor progression and invasion at the primary site and its function in fostering metastatic niches in the liver and lungs. We also discuss emerging clinical strategies to target the CRC TME.

The Versatile Roles of Cancer-Associated Fibroblasts in Colorectal Cancer and Therapeutic Implications

The tumor microenvironment (TME) is populated by abundant cancer-associated fibroblasts (CAFs) that radically influence the disease progression across many cancers, including the colorectal cancer (CRC). In theory, targeting CAFs holds great potential in optimizing CRC treatment. However, attempts to translate the therapeutic benefit of CAFs into clinic practice face many obstacles, largely due to our limited understanding of the heterogeneity in their origins, functions, and mechanisms. In recent years, accumulating evidence has uncovered some cellular precursors and molecular markers of CAFs and also revealed their versatility in impacting various hallmarks of CRC, together helping us to better define the population of CAFs and also paving the way toward their future therapeutic targeting for CRC treatment. In this review, we outline the emerging concept of CAFs in CRC, with an emphasis on their origins, biomarkers, prognostic significance, as well as their functional roles and underlying mechanisms in CRC biology. At last, we discuss the prospect of harnessing CAFs as promising therapeutic targets for the treatment of patients with CRC.

High-Resolution Diffusion-Weighted Imaging for Evaluation of Extramural Tumor Invasion in Primary Rectal Cancer

OBJECTIVE

The aim of this study was to determine the added value of high-resolution diffusion-weighted imaging (DWI) to T2-weighted imaging (T2WI) for evaluation of extramural tumor invasion (EMTI) in patients with primary rectal cancer.

METHODS

Seventy-eight patients who had undergone 3.0-T magnetic resonance imaging including DWI (b = 0, 1000 s/mm2, 2 mm iso-voxel) and subsequent surgery were included. Two blinded radiologists independently read the T2WI first and then the combined DWI set. They recorded their confidence level using a 5-point scale. The diagnostic accuracy was calculated by receiver operating characteristic curve analysis based on the histopathological results as the reference.

RESULTS

The study population consisted of EMTI positive (n = 44) and negative (n = 34). The area under the curve was not significantly increased after adding DWI to T2WI (reader 1, 0.868-0.856, P = 0.5618; reader 2, 0.848-0.865, P = 0.4539).

CONCLUSION

Adding DWI to T2WI showed no additional diagnostic value for the evaluation of EMTI in patients with primary rectal cancer.

Cancer-associated fibroblasts are associated with poor prognosis in solid type of lung adenocarcinoma in a machine learning analysis

Cancer-associated fibroblasts (CAFs) participate in critical processes in the tumor microenvironment, such as extracellular matrix remodeling, reciprocal signaling interactions with cancer cells and crosstalk with infiltrating inflammatory cells. However, the relationships between CAFs and survival are not well known in lung cancer. The aim of this study was to reveal the correlations of CAFs with survival rates, genetic alterations and immune activities. This study reviewed the histological features of 517 patients with lung adenocarcinoma from The Cancer Genome Atlas (TCGA) database. We performed gene set enrichment analysis (GSEA), network-based analysis and survival analysis based on CAFs in four histological types of lung adenocarcinoma: acinar, papillary, micropapillary and solid. We found four hallmark gene sets, the epithelial-mesenchymal transition, angiogenesis, hypoxia, and inflammatory response gene sets, that were associated with the presence of CAFs. CAFs were associated with tumor proliferation, elevated memory CD4+T cells and high CD274 (encoding PD-L1) expression. In the pathway analyses, CAFs were related to blood vessel remodeling, matrix organization, negative regulation of apoptosis and transforming growth factor-β signaling. In the survival analysis of each histological type, CAFs were associated with poor prognosis in the solid type. These results may contribute to the development of therapeutic strategies against lung adenocarcinoma cases in which CAFs are present.

CAFs Interacting With TAMs in Tumor Microenvironment to Enhance Tumorigenesis and Immune Evasion

Cancer associated fibroblasts (CAFs) and tumor associated macrophages (TAMs) are among the most important and abundant players of the tumor microenvironment. CAFs as well as TAMs are known to play pivotal supportive roles in tumor growth and progression. The number of CAF or TAM cells is mostly correlated with poor prognosis. Both CAFs and TAMs are in a reciprocal communication with the tumor cells in the tumor milieu. In addition to such interactions, CAFs and TAMs are also involved in a dynamic and reciprocal interrelationship with each other. Both CAFs and TAMs are capable of altering each other's functions. Here, the current understanding of the distinct mechanisms about the complex interplay between CAFs and TAMs are summarized. In addition, the consequences of such a mutual relationship especially for tumor progression and tumor immune evasion are highlighted, focusing on the synergistic pleiotropic effects. CAFs and TAMs are crucial components of the tumor microenvironment; thus, they may prove to be potential therapeutic targets. A better understanding of the tri-directional interactions of CAFs, TAMs and cancer cells in terms of tumor progression will pave the way for the identification of novel theranostic cues in order to better target the crucial mechanisms of carcinogenesis.

Signaling pathways in cancer-associated fibroblasts and targeted therapy for cancer

To flourish, cancers greatly depend on their surrounding tumor microenvironment (TME), and cancer-associated fibroblasts (CAFs) in TME are critical for cancer occurrence and progression because of their versatile roles in extracellular matrix remodeling, maintenance of stemness, blood vessel formation, modulation of tumor metabolism, immune response, and promotion of cancer cell proliferation, migration, invasion, and therapeutic resistance. CAFs are highly heterogeneous stromal cells and their crosstalk with cancer cells is mediated by a complex and intricate signaling network consisting of transforming growth factor-beta, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin, mitogen-activated protein kinase, Wnt, Janus kinase/signal transducers and activators of transcription, epidermal growth factor receptor, Hippo, and nuclear factor kappa-light-chain-enhancer of activated B cells, etc., signaling pathways. These signals in CAFs exhibit their own special characteristics during the cancer progression and have the potential to be targeted for anticancer therapy. Therefore, a comprehensive understanding of these signaling cascades in interactions between cancer cells and CAFs is necessary to fully realize the pivotal roles of CAFs in cancers. Herein, in this review, we will summarize the enormous amounts of findings on the signals mediating crosstalk of CAFs with cancer cells and its related targets or trials. Further, we hypothesize three potential targeting strategies, including, namely, epithelial-mesenchymal common targets, sequential target perturbation, and crosstalk-directed signaling targets, paving the way for CAF-directed or host cell-directed antitumor therapy.

Collagen biology making inroads into prognosis and treatment of cancer progression and metastasis

Progression through dissemination to tumor-surrounding tissues and metastasis development is a hallmark of cancer that requires continuous cell-to-cell interactions and tissue remodeling. In fact, metastization can be regarded as a tissue disease orchestrated by cancer cells, leading to neoplastic colonization of new organs. Collagen is a major component of the extracellular matrix (ECM), and increasing evidence suggests that it has an important role in cancer progression and metastasis. Desmoplasia and collagen biomarkers have been associated with relapse and death in cancer patients. Despite the increasing interest in ECM and in the desmoplastic process in tumor microenvironment as prognostic factors and therapeutic targets in cancer, further research is required for a better understanding of these aspects of cancer biology. In this review, published evidence correlating collagen with cancer prognosis is retrieved and analyzed, and the role of collagen and its fragments in cancer pathophysiology is discussed.

Germline Profiling and Molecular Characterization of Early Onset Metastatic Colorectal Cancer

Background

Early onset colorectal cancer (EO CRC) is a heterogeneous colorectal cancer subtype with obvious hereditary tendencies and increasing incidence. We sought to determine the susceptibility genes and molecular characteristics of EO CRC.

Methods

330 EO metastatic CRC (mCRC) (≤55 years) and 110 average-onset (AO) mCRC patients (>55 years) were enrolled. Capture-based targeted sequencing was performed on tumor tissue and paired white blood cells using a sequencing panel of 520 genes. The association between molecular alterations and overall survival (OS) was analyzed.

Results

Of the 330 EO mCRC patients, 31 carried pathogenic or likely pathogenic germline mutations, with 16 of them diagnosed with lynch syndrome. Fifteen patients had germline mutations in non-mismatch repair genes, including four in MUTHY, three in RAD50, one in TP53, and eight in other genes. Twenty-nine genes were recurrently mutated in EO mCRC, including TP53, APC, KRAS, SMAD4, and BRCA2. The majority of genomic alterations were comparable between EO and AO mCRC. EO mCRC patients were more likely to have a high tumor mutation burden (p < 0.05). RNF43, RBM10, TSC, and BRAF V600E mutations were more commonly observed in EO mCRC, while APC, ASXL1, DNMT3B, and MET genes were more commonly altered in AO patients. At the pathway level, the WNT pathway was the only differentially mutated pathway between EO and AO mCRC (p < 0.0001). The wild-type WNT pathway (p = 0.0017) and mutated TGF-β pathway (p = 0.023) were associated with unfavorable OS in EO mCRC.

Conclusions

Approximately one in 10 EO mCRC was associated with hereditary tumors. The spectrum of somatic alterations was largely comparable between EO and AO mCRC with several notable differences.

Whole slide imaging and colorectal carcinoma: A validation study for tumor budding and stromal differentiation

Whole slide imaging (WSI) has recently received FDA approval for sign out in surgical pathology and some anticipate this to mature into the gold standard. During this transition, it will be important to validate WSI for its intended use. And many studies have validated whole slide imaging by comparing diagnostic accuracy with that of conventual light microscopy (CLM); however, the assessment of histopathologic markers is prone to much more discrepancy. One of the best examples being tumor-bud scoring in colorectal carcinoma. Other signatures, including stromal differentiation or desmoplastic reaction; could better represent the epithelial-mesenchymal transition. The findings in our study suggest stromal differentiation on both digital and glass slides to be much more reproducible (0.3585-0.9368) when compared to tumor budding (0.0968-0.7871). When comparing interobserver variation between glass and digital slides for three observers; stromal differentiation was more reliable on glass slides (0.4492), when compared to its digital counterpart (0.3016). On the other hand, interobserver variation for tumor bud scoring was more reliable on digital (0.1661), than glass slides (0.1026). Overall, there is significant variation between different observers and reproducibility issues present on conventual light microscopy transfer to digital slides. Although it is possible that too much emphasis is being placed on the concordance of WSI with CLM. In future, applications in artificial intelligence may be key to diagnostic precision and improved patient outcomes.

Stromal categorization in early oral tongue cancer

Stromal categorization has been used to classify many epithelial cancer types. We assessed the desmoplastic reaction and compared its significance with other stromal characteristics in early (cT1-2N0) oral tongue squamous cell carcinoma (OTSCC). In this multi-institutional study, we included 308 cases treated for early OTSCC at five Finnish university hospitals or at the A.C. Camargo Cancer Center in São Paulo, Brazil. The desmoplastic reaction was classified as immature, intermediate, or mature based on the amount of hyalinized keloid-like collagen and myxoid stroma. We compared the prognostic value of the desmoplastic reaction with a stromal grading system based on tumor-stroma ratio and stromal tumor-infiltrating lymphocytes. We found that a high amount of stroma with a weak infiltration of lymphocytes was associated statistically significantly with a worse disease-free survival with a hazard ratio (HR) of 2.68 (95% CI 1.26–5.69), worse overall survival (HR 2.95, 95% CI 1.69–5.15), and poor disease-specific survival (HR 2.66, 95% CI 1.11–6.33). Tumors having a high amount of stroma with a weak infiltration of lymphocytes were also significantly associated with a high rate of local recurrence (HR 4.13, 95% CI 1.67–10.24), but no significant association was found with lymph node metastasis (HR 1.27, 95% CI 0.37–4.35). Categorization of the stroma based on desmoplastic reaction (immature, intermediate, mature) showed a low prognostic value for early OTSCC in all survival analyses (P > 0.05). In conclusion, categorization of the stroma based on the amount of stroma and its infiltrating lymphocytes shows clinical relevance in early OTSCC superior to categorization based on the maturity of stroma.

Immature Stroma and Prognostic Profiling in Colorectal Carcinoma: Development and Validation of Novel Classification Systems

Many pathological characteristics have utility for predicting prognosis in colorectal carcinoma (CRC). Some of the most important include tumor stage (TS), lymph node status (LNS) and tumor budding (TB). Tumor budding is a phenomenon originally described in 1949 as sprouting. TB assessment is not always reliable however, as it is subject to high inter-observer variation. This finding persists despite the current trends for sub-specialty training in surgical pathology. In light of this, new and reproducible histological prognostic markers could change the way we diagnose and manage patients with colorectal carcinoma. Studies have shown that desmoplastic reaction (DR) categorization can actually outperform other conventional prognostic factors, including tumor budding and tumor stage in predicting disease-free survival (DFS). Our study aimed to evaluate and assess the prognostic value of desmoplastic reaction in an American cohort with colorectal cancer using 3 different stromal classification scoring systems. In all three stromal grading systems, immature stroma was the most significant independent prognostic factor in CRC. Currently, none of the reporting protocols for the College of American Pathologists, the Royal College of Pathologists of the United Kingdom, and the Japanese Society for Cancer report on the presence of immature stroma. Importantly, regarding the ability to predict survival outcomes, our novel classification system has the potential to outperform other scoring methodologies.

Functional Interplay Between Collagen Network and Cell Behavior Within Tumor Microenvironment in Colorectal Cancer

Colorectal cancer is the second most common cancer diagnosed in men and the third most commonly occurring in women worldwide. Interactions between cells and the surrounding extracellular matrix (ECM) are involved in tumor development and progression of many types of cancer. The organization of the ECM molecules provides not only physical scaffoldings and dynamic network into which cells are embedded but also allows the control of many cellular behaviors including proliferation, migration, differentiation, and survival leading to homeostasis and morphogenesis regulation. Modifications of ECM composition and mechanical properties during carcinogenesis are critical for tumor initiation and progression. The core matrisome consists of five classes of macromolecules, which are collagens, laminins, fibronectin, proteoglycans, and hyaluronans. In most tissues, fibrillar collagen is the major component of ECM. Cells embedded into fibrillar collagen interact with it through their surface receptors, such as integrins and discoidin domain receptors (DDRs). On the one hand, cells incorporate signals from ECM that modify their functionalities and behaviors. On the other hand, all cells within tumor environment (cancer cells, cancer-associated fibroblasts, endothelial cells, and immune cells) synthesize and secrete matrix macromolecules under the control of multiple extracellular signals. This cell-ECM dialog participates in a dynamic way in ECM formation and its biophysical and biochemical properties. Here, we will review the functional interplay between cells and collagen network within the tumor microenvironment during colorectal cancer progression.

Tumor Budding in Colorectal Carcinoma Showing a Paradoxical Mitotic Index (Via PHH3) With Possible Association to the Tumor Stromal Microenvironment

BACKGROUND

Colorectal carcinomas (CC) are one of the most commonly diagnosed malignancies. Tumor budding (the histologic process of dissociation that occurs at the invasive margin of colorectal cancer), has significant prognostic implications, in that higher tumor budding is associated with adverse histopathologic and clinical outcomes. Because of this prognostic significance, more research is needed to further understand the pathologic and immunohistochemical (IHC) associations pertaining to this important prognostic variable. In this study, we will further evaluate selective clinopathologic and IHC variables with possible association to tumor budding.

DESIGN

A total of 234 cases of CC diagnosed in our health system were retrospectively reviewed and routine hematoxylin and eosin-stained slides of these cases were collected. A representative slide for tumor budding was selected per case and selective IHC staining was performed. Clinicopathologic data were collected for each case and analyzed in relation to tumor budding scores. In exploratory analyses, tumor budding scores per individual investigator and consensus tumor budding scores were compared with selected IHC stains (MLH1, PMS2, and PHH3) as well as numerous clinicopathologic variables.

RESULTS

We found a paradoxical association between tumor budding and mitosis score using PHH3 immunostaining in univariate and multivariable analysis. Furthermore, patients with intact nuclear expression for MLH1 and/or PMS2 are more likely to have higher tumor budding compared with patients with lost expression. For multivariable analysis, the following covariates were significantly associated with higher tumor budding: the presence of lymphovascular invasion, higher pathologic tumor stage, and finally infiltrating border was more likely to be associated with higher tumor budding compared with cases with a pushing border. Regarding nonmucinous versus mucinous CC, nonmucinous adenocarcinoma (MCA) was more likely to be associated with higher tumor budding compared with MCA.

CONCLUSION

Numerous clinicopathologic variables were found to be associated with tumor budding including lymphovascular invasion, tumor stage, infiltrating tumor border, non-MCA was more likely to be associated with higher tumor budding compared with MCA, possibly related to MUC-2 and MSI. Furthermore, regarding the paradoxical association between tumor budding and mitosis score using a PHH3 immunostaining (high tumor budding having lower mitosis), this is possibly related to the tumoral stomal microenvironment and cancer associated fibroblasts. An idea for a future study would be to look at the maturity of cancer-associated fibroblasts (immature vs. mature) and the tumoral stroma microenvironment, with regards to markers of tumor aggressiveness such as mitosis. In addition, we found that patients with intact nuclear expression for MLH1 and/or PMS2 were more likely to have higher tumor budding compared with patients with lost expression, possibly related to mismatch repair CC's not being as reliant on tumor budding. Future research will hopefully concede further insight into the variables that affect tumor budding, especially regarding the tumoral microenvironment and variations between different patient populations, inclusive of patients lacking activity of the mismatch repair. Ultimately, this will allow for better prognostic information, and more precise treatment modalities.