The landscape of metastatic progression patterns across major human cancers

Characteristics of clear cell renal cell carcinoma metastases to the thyroid gland: A systematic review

BACKGROUND

Thyroid gland is an uncommon site for metastases from clear cell renal cell carcinoma (CCRCC) and literature is scarce. Due to the variable and often long lag time before development of metastases in patients with CCRCC, thyroid nodules may be misdiagnosed initially as benign. This systematic review aims at a better understanding of the nature of these metastases.

METHODS

A bibliographic search was performed using PubMed (1990-2019), key words being “renal cell carcinoma, thyroid, kidney cancer, clear cell.” 147 cases were analyzed. The patient’s characteristics assessed were: age, sex, stage, size of metastases, lag time, diagnostic modality, initial symptoms, treatment and outcome in last documented follow up. Binary logistic regression, Spearman’s rho and ANOVA were used to identify differences between the existing variables.

RESULTS

The mean age (± SD) was 64 ± (10) years in males and 64 (± 11) in females. The mean lag time to diagnosis of thyroid metastases was 8.7 (± 6.3) years. Gender distribution of the patients was 46.3% male, 52.4% female. There was a weak correlation between lag time and size of metastases, not statistically significant. Size of metastases was significantly higher in symptomatic patients (6.06 ± 3.51 cm) compared to those with painless mass (4.6 ± 0.29 cm) and asymptomatic ones (3.93 ± 1.99 cm) (P = 0.03). Fine Needle Aspiration was diagnostic in 29.4% of cases, 47.1% were non diagnostic. Most patients (80.3%) underwent thyroid surgery. At 1 year follow up, 55.6% of patients operated were alive versus 35.3% who did not have surgery, though this was not statistically significant (P = 0.1).

CONCLUSION

A larger size of thyroid metastasis was more likely to present with symptomatology. A high index of suspicion is warranted when evaluating thyroid nodules in CCRCC patients. There was no significant difference in outcome between patients who underwent surgery and those who did not. With the wider use of immune check-point inhibitors and tyrosine kinase inhibitors in metastatic CCRCC, surgery may eventually be reserved only for palliative purposes.

Immune Microenvironment of Brain Metastases-Are Microglia and Other Brain Macrophages Little Helpers?

Brain metastases are common intracranial neoplasms and their frequency increases with prolonged survival of cancer patients. New pharmaceuticals targeting oncogenic kinases and immune checkpoint inhibitors augment both overall and progression-free survival in patients with brain metastases, but are not fully successful in reducing metastatic burden and still a majority of oncologic patients die due to dissemination of the disease. Despite therapy advancements, median survival of patients with brain metastases is several months, although it may vary in different types or subtypes of cancer. Contribution of the innate immune system to cancer progression is well established. Tumor-associated macrophages (TAMs), instead of launching antitumor responses, promote extracellular matrix degradation, secrete immunosuppressive cytokines, promote neoangiogenesis and tumor growth. While their roles as pro-tumorigenic cells facilitating tissue remodeling, invasion and metastasis is well documented, much less is known about the immune microenvironment of brain metastases and roles of specific immune cells in those processes. The central nervous system (CNS) is armed in resident myeloid cells: microglia and perivascular macrophages which colonize CNS in early development and maintain homeostasis in brain parenchyma and at brain-blood vessels interfaces. In this study we discuss available data on the immune composition of most common brain metastases, focusing on interactions between metastatic cancer cells and microglia, perivascular and meningeal macrophages. Cancer cells ‘highjack’ several CNS protective mechanisms and may employ microglia and CNS-border associated macrophages into helping cancer cells to colonize a pre-metastatic niche. We describe emerging molecular insights into mechanisms governing communication between microglia and metastatic cancer cells that culminate in activation of CNS resident microglia and trafficking of monocytic cells from the periphery. We present mechanisms controlling those processes in brain metastases and hypothesize on potential therapeutic approaches. In summary, microglia and non-parenchymal brain macrophages are involved in multiple stages of a metastatic disease and, unlike tumor cells, are genetically stable and predictable, which makes them an attractive target for anticancer therapies.

Treatment of dedifferentiated chordoma: a retrospective study from a large volume cancer center

OBJECTIVE

Dedifferentiated chordomas (DC) are genetically and clinically distinct from conventional chordomas (CC), exhibiting frequent SMARCB1 alterations and a more aggressive clinical course. We compared treatment and outcomes of DC and CC patients in a retrospective cohort study from a single, large-volume cancer center.

METHODS

Overall, 11 DC patients were identified from 1994 to 2017 along with a cohort of 68 historical control patients with CC treated during the same time frame. Clinical variables and outcomes were collected from the medical record and Wilcoxon rank sum or Fisher exact tests were used to make comparisons between the two groups. Kaplan-Meier survival analysis and log-rank tests were used to compare DC and CC overall survival.

RESULTS

DC demonstrated a bimodal age distribution at presentation (36% age 0-24; 64% age > 50). DC patients more commonly presented with metastatic disease than CC patients (36% vs. 3% p = 0.000). DC patients had significantly shorter time to local treatment failure after radiation therapy (11.1 months vs. 34.1 months, p = 0.000). The rate of distant metastasis following treatment was significantly higher in DC compared to CC (57% vs. 5%, p = 0.000). The median overall survival after diagnosis for DC was 20 months (95% CI 0-48 months) compared to 155 months (95% CI 94-216 months) for CC (p = 0.007).

CONCLUSION

DC patients exhibit significantly higher rates of both synchronous and metachronous metastases, as well as shorter overall survival rates compared to conventional chordoma. The relatively poor survival outcomes with conventional therapies indicate the need to study targeted therapies for the treatment of DC.

A Point-based Histologic Scoring System for Hepatocellular Carcinoma Can Stratify Risk of Posttransplant Tumor Recurrence

Eligibility for liver transplant is most commonly decided by measuring tumor size and number on radiographic imaging. However, this method often underestimates the extent of disease. Evaluation of tumor histology has been shown to improve risk stratification when compared with imaging-based transplant criteria, but the World Health Organization (WHO) guidelines for grading hepatocellular carcinoma (HCC) are imprecise and require subjective interpretation by the pathologist. We performed a retrospective analysis of 190 explanted livers containing HCC and correlated histologic features with posttransplant recurrence to formulate a three-tiered, point-based scoring system that categorizes tumors as having a low, intermediate, or high risk of recurrence. Our Recurrence Risk Assessment Score (RRAS) evaluates tumor architecture and specific cytologic features-nuclear pleomorphism, cytoplasmic amphophilia, and nuclear-to-cytoplasmic ratio-showing superior stratification of HCC recurrence risk compared with imaging criteria and grade assigned by WHO methodology. Stratifying tumors using RRAS criteria, the rate of recurrence after transplant was 0% among low-risk tumors (compared with 3% of well-differentiated tumors), 12% among intermediate-risk tumors (compared with 15% of moderately differentiated tumors), and 54% among high-risk tumors (compared with 29% of poorly differentiated tumors). Receiver operating characteristic analysis shows significantly improved performance of RRAS criteria in predicting HCC recurrence compared with WHO grade (area under curve of 0.841 and 0.671, respectively; P=0.0061). Our results indicate that evaluation of tumor histology offers superior prediction of recurrence risk following liver transplantation compared with radiographic criteria, and that the RRAS system better stratifies recurrence risk compared with HCC grading by WHO methodology.

Depletion of Ras Suppressor-1 (RSU-1) promotes cell invasion of breast cancer cells through a compensatory upregulation of a truncated isoform

Extracellular matrix (ECM)-adhesion proteins and actin cytoskeleton are pivotal in cancer cell invasion. Ras Suppressor-1 (RSU-1), a cell-ECM adhesion protein that interacts with PINCH-1, thus being connected to Integrin Linked Kinase (ILK), alpha-parvin (PARVA), and actin cytoskeleton, is up-regulated in metastatic breast cancer (BC) samples. Apart from the originally-identified gene (RSU-1L), an alternatively-spliced isoform (RSU-1-X1) has been reported. We used non-invasive MCF-7 cells, expressing only RSU-1L, and highly invasive MDA-MB-231-LM2 expressing both isoforms and generated stable shRNA-transduced cells lacking RSU-1L, while the truncated RSU-1-X1 isoform was depleted by siRNA-mediated silencing. RSU-1L depletion in MCF-7 cells resulted in complete abrogation of tumor spheroid invasion in three-dimensional collagen gels, whereas it promoted MDA-MB-231-LM2 invasion, through a compensatory upregulation of RSU-1-X1. When RSU-1-X1 was also eliminated, RSU-1L-depletion-induced migration and invasion were drastically reduced being accompanied by reduced urokinase plasminogen activator expression. Protein expression analysis in 23 human BC samples corroborated our findings showing RSU-1L to be upregulated and RSU-1-X1 downregulated in metastatic samples. We demonstrate for the first time, that both RSU-1 isoforms promote invasion in vitro while RSU-1L elimination induces RSU-1-X1 upregulation to compensate for the loss. Hence, we propose that both isoforms should be blocked to effectively eliminate metastasis.

TBL1XR1 is involved in c-Met-mediated tumorigenesis of human nonsmall cell lung cancer

Nonsmall cell lung carcinoma (NSCLC) contributes to the highest number of cancer deaths globally. Metastases and chemoresistance are two major confounders to the treatment efficacy in NSCLC. Transducin (β)-like 1 X-linked receptor 1 (TBL1XR1) has been associated with high rates of metastases in breast, gastric, and stomach cancers. However, the role of TBL1XR1 in lung cancers remains underexplored. We selected matched and cancerous lung tissues to establish the upregulation of TBL1XR1. Using in vitro assays, we assessed the influence of TBL1XR1 on various cancer phenotypes, namely cell proliferation, chemoresistance, invasion, and metastases in a CRISPR-Cas9-mediated knock out model (A549 cells), and H460 cell lines overexpressing TBL1XR1. We found that TBL1XR1 is overexpressed in NSCLC tissue and patient sera in comparison to paired adjacent normal tissue. Overexpression of TBL1XR1 in NSCLC cell lines mediates cell survival, proliferation, and metastases. TBL1XR1 was found to regulate MEK and Akt pathways through their master regulator c-Met. We observed that activation of c-Met is downregulated in the absence of TBL1XR1. Our study strengthens the contention that TBL1XR1 is a biomarker for prognosis of NSCLC. It may also be considered as an adjunct or core therapeutic target to overcome cisplatin resistance in lung cancers.

The miRNA hsa-miR-6515-3p potentially contributes to lncRNA H19-mediated-lung cancer metastasis

Aberrant expression of long noncoding RNAs (lncRNAs) contributes to all phenotypes of cancer including metastasis, which is a major cause of death in many advanced malignancies. One particular lncRNA, H19, is found to be a crucial player in cancer progression by modulating multiple microRNAs (miRNAs). In this study, we screened miRNAs possibly associated with H19 using lung carcinoma cell lines and patient with lung cancer tissues, and selected one possible hit, hsa‐miR‐6515‐3p, to perform in vitro functional assays. Its inhibition leads to decreased proliferation and migration of SPC‐A1 lung cancer cells and is in good correlation with H19‐knockdown groups. These results indicate that H19 may be an epigenetic regulator of miR‐6515‐3p, and its dysregulation may contribute to lung cancer progression and metastasis.

Metastasis Organotropism: Redefining the Congenial Soil

Metastasis is the most devastating stage of cancer progression and causes the majority of cancer-related deaths. Clinical observations suggest that most cancers metastasize to specific organs, a process known as "organotropism." Elucidating the underlying mechanisms may help identify targets and treatment strategies to benefit patients. This review summarizes recent findings on tumor-intrinsic properties and their interaction with unique features of host organs, which together determine organ-specific metastatic behaviors. Emerging insights related to the roles of metabolic changes, the immune landscapes of target organs, and variation in epithelial-mesenchymal transitions open avenues for future studies of metastasis organotropism.

Lactate and cancer: spinal metastases and potential therapeutic targets (part 2)

Metastatic spine disease is a heterogeneous clinical condition commonly requiring surgical intervention. Despite this heterogeneity, all cases share the common theme of altered tumor metabolism, characterized by aerobic glycolysis and high lactate production. Here we review the existing literature on lactate metabolism as it pertains to tumor progression, metastasis, and the formation of painful bone lesions. We included articles from the English literature addressing the role of lactate metabolism in the following: (I) primary tumor aggressiveness, (II) local tissue invasion, (III) metastasis formation, and (IV) generation of oncologic pain. We also report current investigations into restoring normal lactate metabolism as a means of impeding tumor growth and the formation of bony metastases. Both in vivo and in vitro experiments suggest that high lactate levels may be necessary for tumor cell growth, as small molecules inhibitors of lactate dehydrogenase (LDH5/LDHA) decrease both the rate of tumor growth and formation of metastases. Additionally, in vitro evidence strongly implicates lactate in tumor cell migration by driving the amoeboid movements of these cells. Acidification of the local bony tissue by excess lactate production activates CGRP⁺ neurons in the bone marrow and periosteum to generate oncologic bone pain. High lactate may also increase expression of acid sensing receptors in these neurons to generate the neuropathic pain seen in some patients with metastatic disease. Lastly, investigation into lactate-directed therapeutics is still early in development. Initial preclinical trials looking at LDH5/LDHA inhibitors as well as inhibitors of lactate transporters (MCT1) have demonstrated promise, but clinical work has been restricted to a single phase I trial. Lactate appears to play a crucial role in the pathogenesis of metastatic spine disease. Efforts are ongoing to identify small molecules inhibitors of targets in the lactogenic pathway capable of preventing the formation of osseous metastatic disease.

Intra- and interobserver reliability of the Spinal Instability Neoplastic Score system for instability in spine metastases: a systematic review and meta-analysis

Mechanical instability is one of the two main indications for surgical intervention in patients with metastatic spine disease. Since its publication in 2010, the Spinal Instability Neoplastic Score (SINS) has been the most commonly used means of assessing mechanical instability. To prove clinically valuable though, diagnostic tests must demonstrate consistency across measures and across observers. Here we report a systematic review and meta-analysis of all prior reports of intraobserver and interobserver reliability of the SINS score. To identify articles, we queried the PubMed, CINAHL, EMBASE, Cochrane, and Web of Science databases for all full-text English articles reporting interobserver or intraobserver reliability for the SINS score, category, or a domain of the SINS score. Articles reporting confidence intervals for these metrics were then subjected to meta-analysis to identify pooled estimates of reliability. Of 167 unique studies identified, seven met inclusion criteria and were subjected to qualitative review and meta-analysis. Intraobserver reliability for SINS score was found to be near perfect [estimate =0.815; 90% CI (0.661-0.969)] and interobserver reliability was substantial [0.673; (0.227-1.12)]. Intraobserver and interobserver reliability among spine surgeons was significantly better than reliability across all observers (both P<0.0001). Qualitative analysis suggested that increased surgeon experience may be associated with greater intraobserver and interobserver reliability among spine surgeons. On the whole, meta-analysis of the available literature suggests SINS to have good intraobserver and interobserver reliability, giving it the potential to be a valuable guide to the management of patients with spinal metastases. Further research is required to demonstrate that SINS score correlates with the clinical decision to stabilize.

Up-regulation of Insulin-like Growth Factor Binding Protein-3 Is Associated with Brain Metastasis in Lung Adenocarcinoma

The brain is the most common metastatic site of lung adenocarcinoma; however, the mechanism of this selective metastasis remains unclear. We aimed to verify the hypothesis that exposure of tumor cells to the brain microenvironment leads to changes in their gene expression, which promotes their oriented transfer to the brain. A549 and H1299 lung adenocarcinoma cells were exposed to human astrocyte-conditioned medium to simulate the brain microenvironment. Microarray analysis was used to identify differentially expressed genes, which were confirmed by quantitative real-time PCR and western blotting. Knockdown experiments using microRNAs and the overexpression of genes by cell transfection were performed in addition to migration and invasion assays. In vitro findings were confirmed in clinical specimens using immunohistochemistry. We found and confirmed a significant increase in insulin-like growth factor binding protein-3 (IGFBP3) levels. Our results also showed that the up-regulation of IGFBP3 promoted A549 cell epithelial-mesenchymal transition, migration, and invasion, while the knockdown of IGFBP3 resulted in decreased cell motility. We also found that Transforming growth factor-β (TGF-β)/Mothers against decapentaplegic homolog 4 (Smad4)-induced epithelial-mesenchymal transition was likely IGFBP3-dependent in A549 cells. Finally, expression of IGFBP3 was significantly elevated in pulmonary cancer tissues and intracranial metastatic tissues. Our data indicate that up-regulation of IGFBP3 might mediate brain metastasis in lung adenocarcinoma, which makes it a potential therapeutic target.

Several genotypes, one phenotype: PIK3CA/AKT1 mutation-negative hidradenoma papilliferum show genetic lesions in other components of the signalling network

About 60-70% of hidradenoma papilliferum (HP), a benign tumour of the anogenital region, were recently described to harbour mutations in major driver genes of the PI3K/AKT/MAPK-signalling pathways. However, the underlying genetic defects of the non-mutant cases are still unknown. Using a 409 gene panel, we employed targeted next generation sequencing to investigate the mutational landscape in a cohort of seven PI3K/AKT-negative cases and five cases with known hotspot mutations in either PIK3CA or AKT1. In total, we identified 29 mutations in 22 of 409 genes. The four cases with PIK3CA hotspot mutations carried no or only few additional mutations. The AKT1 hotspot mutated case harboured additional mutations in four genes (SYNE1, ADAMTS20, EP400 and CASC5). At least two of these genes are involved in or contribute to the PI3K/AKT-pathway. In the seven non-hotspot mutated cases we observed 18 mutations. Each case carried at least one mutation in a gene contributing to or involved in PI3K/AKT-signalling. Affected genes were PIK3CA (n=1, non-hotspot mutation), PIK3R1 (n=3), SYNE1, AR, IL6ST, PDGFRB, KMT2C, AR, BTK, DST, KAT6A, BRD3, RNF213, USP9X, ADGRB3, MAGI1, and IL7R (each gene mutated once). The identified PIK3CA and PIK3R1 mutations lead to constitutive activated PI3K/AKT-signalling. In conclusion, we demonstrate the genetic basis of HP in all cases. Our data suggest that tumourigenic alterations in the PI3K/AKT-pathway are indispensable in HP and establish a homogenous morphomolecular entity with a functionally converging and selecting tumourigenic mechanism.

Metastasis inhibition in breast cancer by targeting cancer cell extravasation

The spread of cells from primary tumors toward distant tissues and organs, also known as metastasis, is responsible for most cancer-associated deaths. The metastasis cascade comprises a series of events, characterized by the displacement of tumor cells (TCs) from the primary tumor to distant organs by traveling through the bloodstream, and their subsequent colonization. The first step in metastasis involves loss of cell-cell and cell-matrix adhesions, increased invasiveness and migratory abilities, leading to intravasation of TCs into the blood or lymphatic vessels. Stationary TCs must undergo the process of epithelial-mesenchymal transition in order to achieve this migratory and invasive phenotype. Circulating tumor cells that have survived in the circulation and left the blood or lymphatic vessels will reach distant sites where they may stay dormant for many years or grow to form secondary tumors. To do this, cells need to go through the mesenchymal-epithelial transition to revert the phenotype in order to regain epithelial cell-to-cell junctions, grow and become a clinically relevant and detectable tumor mass. This work will review the main steps of the metastatic cascade and describe some strategies to inhibit metastasis by reducing cancer cell extravasation presenting recent studies in the context of breast cancer.

Metastatic Tumor-in-a-Dish, a Novel Multicellular Organoid to Study Lung Colonization and Predict Therapeutic Response

Metastasis is a major cause of cancer-related deaths. A dearth of preclinical models that recapitulate the metastatic microenvironment has impeded the development of therapeutic agents that are effective against metastatic disease. Because the majority of solid tumors metastasize to the lung, we developed a multicellular lung organoid that mimics the lung microenvironment with air sac-like structures and production of lung surfactant protein. We used these cultures, called primitive lung-in-a-dish (PLiD), to recreate metastatic disease using primary and established cancer cells. The metastatic tumor-in-a-dish (mTiD) cultures resemble the architecture of metastatic tumors in the lung, including angiogenesis. Pretreating PLiD with tumor exosomes enhanced cancer cell colonization. We next tested the response of primary and established cancer cells to current chemotherapeutic agents and an anti-VEGF antibody in mTiD against cancer cells in two-dimensional (2D) or 3D cultures. The response of primary patient-derived colon and ovarian tumor cells to therapy in mTiD cultures matched the response of the patient in the clinic, but not in 2D or single-cell-type 3D cultures. The sensitive mTiD cultures also produced significantly lower circulating markers for cancer similar to that seen in patients who responded to therapy. Thus, we have developed a novel method for lung colonization in vitro, a final stage in tumor metastasis. Moreover, the technique has significant utility in precision/personalized medicine, wherein this phenotypic screen can be coupled with current DNA pharmacogenetics to identify the ideal therapeutic agent, thereby increasing the probability of response to treatment while reducing unnecessary side effects. SIGNIFICANCE: A lung organoid that exhibits characteristics of a normal human lung is developed to study the biology of metastatic disease and therapeutic intervention.

MicroRNAs in Female Malignancies

MicroRNAs (miRNAs) are endogenous 22-nucleotide RNAs that can play a fundamental regulatory role in the gene expression of various organisms. Current research suggests that miRNAs can assume pivotal roles in carcinogenesis. In this article, through bioinformatics mining and computational analysis, we determine a single miRNA commonly involved in the development of breast, cervical, endometrial, ovarian, and vulvar cancer, whereas we underline the existence of 7 more miRNAs common in all examined malignancies with the exception of vulvar cancer. Furthermore, we identify their target genes and encoded biological functions. We also analyze common biological processes on which all of the identified miRNAs act and we suggest a potential mechanism of action. In addition, we analyze exclusive miRNAs among the examined malignancies and bioinformatically explore their functionality. Collectively, our data can be employed in in vitro assays as a stepping stone in the identification of a universal machinery that is derailed in female malignancies, whereas exclusive miRNAs may be employed as putative targets for future chemotherapeutic agents or cancer-specific biomarkers.

Circulation patterns and seed-soil compatibility factors cooperate to cause cancer organ-specific metastasis

Despite the recognition of the lethality of cancer metastasis and the importance of developing specific anti-metastasis therapies directed at the cancer metastatic cascade, the dynamics of cancer metastasis remains poorly understood. In this study, we examined the dynamics of circulating tumor cell (CTC) survival in the bloodstream using experimental mouse models. CTCs were arrested in the capillaries by adhesion to vascular endothelium within a few minutes after injection into the bloodstream. The loss of CTCs from the circulation followed a bi-phasic decay pattern, with the number of CTCs in the bloodstream being closely associated with the number of blood circulation cycles. The calculated in vivo Vd (apparent volume of distribution) of the CTC revealed organ specific binding of the CTCs. Moreover, confocal microscopy, in vivo fluorescence imaging in syngeneic mouse metastatic models and analysis of blood circulation patterns support the notion of organ-specific tumor metastasis. The present study suggests that organ-specific tumor metastasis is influenced by cooperation between blood circulation patterns and 'seed-soil' compatibility factors. These new findings provide further insights for optimized cancer metastatic prevention strategies such as by creating a hostile circulation microenvironment and targeting the organ-specific 'seed-soil' compatibility factors.

Validating Comprehensive Next-Generation Sequencing Results for Precision Oncology: The NCT/DKTK Molecularly Aided Stratification for Tumor Eradication Research Experience

Purpose

Rapidly evolving genomics technologies, in particular comprehensive next-generation sequencing (NGS), have led to exponential growth in the understanding of cancer biology, shifting oncology toward personalized treatment strategies. However, comprehensive NGS approaches, such as whole-exome sequencing, have limitations that are related to the technology itself as well as to the input source. Hence, clinical implementation of comprehensive NGS in a quality-controlled diagnostic workflow requires both the standardization of sequencing procedures and continuous validation of sequencing results by orthogonal methods in an ongoing program to enable the determination of key test parameters and continuous improvement of NGS and bioinformatics pipelines.

Patients and Methods

We present validation data on 220 patients who were enrolled between 2013 and 2016 in a multi-institutional, genomics-guided precision oncology program (Molecularly Aided Stratification for Tumor Eradication Research) of the National Center for Tumor Diseases Heidelberg and the German Cancer Consortium.

Results

More than 90% of clinically actionable genomic alterations identified by combined whole-exome sequencing and transcriptome sequencing were successfully validated, with varying frequencies of discordant results across different types of alterations (fusions, 3.7%; single-nucleotide variants, 2.6%; amplifications, 1.1%; overexpression, 0.9%; deletions, 0.6%). The implementation of new computational methods for NGS data analysis led to a substantial improvement of gene fusion calling over time.

Conclusion

Collectively, these data demonstrate the value of a rigorous validation program that partners with comprehensive NGS to successfully implement and continuously improve cancer precision medicine in a clinical setting.

Clinical landscape of cancer metastases

Population-based data on metastatic patterns are lacking because cancer registries seldom record metastases. This study uses a novel population-based approach to identify metastases and describes metastatic pathways from 14 common primary cancers to 12 specific metastatic sites. A total of 179 581 patients with metastatic cancer were identified from the Swedish Cancer Registry and metastatic sites were identified using the Cause of Death Register and the National Patient Register. Patterns of metastatic spread were described across age and sex. In men, colorectal cancer was the main source of lung, peritoneal, and liver metastases. Lung cancer was the main origin of pleural and nervous system metastases. Prostate cancer dominated bone metastases but had minor contribution to other metastatic sites. Among women, breast cancer was the dominant origin of most metastatic sites, with the exception of peritoneum which was ruled by metastases from the ovary. As other exceptions, for nervous system metastases, lung cancer was the origin of metastases somewhat more frequently than breast cancer and for liver metastases, colorectal cancer was the main origin instead of breast cancer. The present achievement was to implement the first nationwide description of clinical landscape of cancer metastases, with an aim to serve as a reliable source for clinicians and researchers.

Prognostic and risk factors in patients with metastatic bone disease of an upper extremity

Background

The aim of this study was to evaluate survival of metastatic bone disease of an upper extremity, and to identify the prognostic factors that influence survival.

Methods

Patients with metastatic bone disease of an upper extremity between 2008 and 2015 were reviewed from the database of a tertiary university hospital.

Results

Of 102 patients, 48 males and 54 females with a median age of 61 (range, 28–82 years), the humerus (64.7%), clavicle (13.7%), and scapula (12.7%) were the common sites for bone metastasis of an upper extremity. Fifty-nine (57.8%) presented with pathologic fracture. No history of cancer was found in 76.5% of patients. The mean onset of metastatic bone disease after the first diagnosis of primary cancer was 4.74 ± 14.07 months (range, 0–84 months). Lung (31.4%) was the most common primary cancer followed by liver (14.7%), breast (12.7%), thyroid (7.8%), and renal (3.9%). Eighty-two cases (80.39%) died from the disease such that the median survival was 4.08 months (95% CI 2.57–6.17). The significant risk factors were the type of primary tumor (P < 0.001, HR = 4.44; 95% CI, 1.99–9.90) and ECOG performance status (P = 0.021, HR = 2.11, 95% CI 1.12–3.99).

Conclusions

Patients with metastatic bone disease of an upper extremity have a limited life expectancy. The type of primary tumor and ECOG performance status were the important prognostic factors that influenced overall survival. Our data help in the management of patients, families, and doctors, so as to avoid over- or under-treatment.

Cell Adhesion and Matrix Stiffness: Coordinating Cancer Cell Invasion and Metastasis

Metastasis is a multistep process in which tumor extracellular matrix (ECM) and cancer cell cytoskeleton interactions are pivotal. ECM is connected, through integrins, to the cell’s adhesome at cell–ECM adhesion sites and through them to the actin cytoskeleton and various downstream signaling pathways that enable the cell to respond to external stimuli in a coordinated manner. Cues from cell-adhesion proteins are fundamental for defining the invasive potential of cancer cells, and many of these proteins have been proposed as potent targets for inhibiting cancer cell invasion and thus, metastasis. In addition, ECM accumulation is quite frequent within the tumor microenvironment leading in many cases to an intense fibrotic response, known as desmoplasia, and tumor stiffening. Stiffening is not only required for the tumor to be able to displace the host tissue and grow in size but also contributes to cell–ECM interactions and can promote cancer cell invasion to surrounding tissues. Here, we review the role of cell adhesion and matrix stiffness in cancer cell invasion and metastasis.

Periostin antisense oligonucleotide suppresses bleomycin-induced formation of a lung premetastatic niche for melanoma

Metastasis is the leading cause of cancer death. A tumor‐supportive microenvironment, or premetastatic niche, at potential secondary tumor sites plays an important role in metastasis, especially in tumor cell colonization. Although a fibrotic milieu is known to promote tumorigenesis and metastasis, the underlying molecular contributors to this effect have remained unclear. Here we show that periostin, a component of the extracellular matrix that functions in tissue remodeling, has a key role in formation of a fibrotic environment that promotes tumor metastatic colonization. We found that periostin was widely expressed in fibrotic lesions of mice with bleomycin‐induced lung fibrosis, and that up‐regulation of periostin expression coincided with activation of myofibroblasts positive for α‐smooth muscle actin. We established a lung metastasis model for B16 murine melanoma cells and showed that metastatic colonization of the lung by these cells was markedly promoted by bleomycin‐induced lung fibrosis. Inhibition of periostin expression by giving an intratracheal antisense oligonucleotide targeting periostin mRNA was found to suppress bleomycin‐induced lung fibrosis and thereby to attenuate metastatic colonization of the lung by melanoma cells. Our results indicate that periostin is a key player in the development of bleomycin‐induced fibrosis and consequent enhancement of tumor cell colonization in the lung. Our results therefore implicate periostin as a potential target for prevention or treatment of lung metastasis.

Organ-specific metastasis of breast cancer: molecular and cellular mechanisms underlying lung metastasis

BACKGROUND

Breast cancer (BC) is the most common type of cancer in women and the second cause of cancer-related mortality world-wide. The majority of BC-related deaths is due to metastasis. Bone, lung, brain and liver are the primary target sites of BC metastasis. The clinical implications and mechanisms underlying bone metastasis have been reviewed before. Given the fact that BC lung metastasis (BCLM) usually produces symptoms only after the lungs have been vastly occupied with metastatic tumor masses, it is of paramount importance for diagnostic and prognostic, as well as therapeutic purposes to comprehend the molecular and cellular mechanisms underlying BCLM. Here, we review current insights into the organ-specificity of BC metastasis, including the role of cancer stem cells in triggering BC spread, the traveling of tumor cells in the blood stream and their migration across endothelial barriers, their adaptation to the lung microenvironment and the initiation of metastatic colonization within the lung.

CONCLUSIONS

Detailed understanding of the mechanisms underlying BCLM will shed a new light on the identification of novel molecular targets to impede daunting pulmonary metastases in patients with breast cancer.

Racial/ethnic disparities in de novo metastases sites and survival outcomes for patients with primary breast, colorectal, and prostate cancer

Racial disparities in cancer mortality still exist despite improvements in treatment strategies leading to improved survival for many cancer types. In this study, we described race/ethnic differences in patterns of de novo metastasis and evaluated the association between site of de novo metastasis and breast, prostate, and colorectal cancer mortality. Data were obtained from the Surveillance Epidemiology and Ends Results (SEER) database from 2010 to 2013 and included 520,147 patients ages ≥40 years with primary diagnosis of breast, colorectal, or prostate cancer. Site and frequency of de novo metastases to four sites (bone, brain, liver, and lung) were compared by race/ethnicity using descriptive statistics, and survival differences examined using extended Cox regression models in SAS 9.4. Overall, non‐Hispanic (NH) Blacks (11%) were more likely to present with de novo metastasis compared with NH‐Whites (9%) or Hispanics (10%). Among patients with breast cancer, NH‐Blacks were more likely to have metastasis to the bone, (OR: 1.25, 95% CI: 1.15–1.37), brain (OR: 2.26, 95% CI: 1.57–3.25), or liver (OR: 1.62, 95% CI: 1.35–1.93), while Hispanics were less likely to have metastasis to the liver (OR: 0.76, 95% CI: 0.60–0.97) compared with NH‐Whites. Among patients with prostate cancer, NH‐Blacks (1.39, 95% CI: 1.31–1.48) and Hispanics (1.39, 95% CI: 1.29–1.49) were more likely to have metastasis to the bone. Metastasis to any of the four sites evaluated increased overall mortality by threefold (for breast cancer and metastasis to bone) to 17‐fold (for prostate cancer and metastasis to liver). Racial disparities in mortality remained after adjusting for metastasis site in all cancer types evaluated. De novo metastasis is a major contributor to cancer mortality in USA with racial differences in the site, frequency, and associated survival.

Metastatic spread in patients with gastric cancer

Background

The epidemiology of metastatic gastric cancer is unexplored because cancer registries seldom cover metastatic involvement apart from “present or not”. We used a novel approach by utilizing Swedish registers to assess metastatic spread in gastric cancer. To our knowledge, this is the first nationwide description of metastases in gastric cancer.

Results

The most common sites of metastasis were liver (in 48% of metastatic cancer patients), peritoneum (32%), lung (15%), and bone (12%). Metastases to the lung, nervous system, and bone were more frequent in cardia cancer and men, whereas non-cardia cancer more frequently metastasized within the peritoneum. Signet ring adenocarcinomas more frequently metastasized within the peritoneum, bone and ovaries, and less frequently to the lungs and liver compared with generic adenocarcinoma. The liver and the peritoneum were commonly single metastases while lung metastases occurred frequently together with liver metastases. The median survival in metastatic gastric cancer was 3 months, worst among those with bone and liver metastases (2 months).

Methods

A total of 7,559 patients with gastric cancer were identified. Metastatic patterns and survival depending on sex, age, stage, anatomical location (cardia and non-cardia), and histological type were assessed.

Conclusions

The patterns of metastasis differ notably depending on histological type. Cardia cancer exhibits a completely different metastatic behavior than non-cardia cancer. Awareness of the differing patterns may guide in tailored diagnosis of metastases. Survivors from cardia cancer would benefit from increased surveillance of extraperitoneal metastases. Bone metastases should be considered in patients with signet ring adenocarcinoma if symptoms emerge.

Cancer Stem Cells in Metastasis Therapy

Tumors consists of subpopulation of cells in which each subtype has contributes to tumor progression. Specifically one subtype known as cancer stem cells are associated with the initiation, progression, resistance to conventional therapies and metastasis. Metastasis is leading cause of cancer related deaths. Overall it is important to consider cancer as a whole in which a mutated cell proliferating indefinitely and forming its hierarchy consisting of subgroups with different molecular signatures. To be able to target this disease we need to evaluate every step including initiation, progression, survival, angiogenesis and finally migration and repopulation. Cancer stem cells do play vital roles in each step however when metastasis can be stopped or eliminated we talk about saving a life or improving its quality. Considering how deeply these cancer stem like cells affect the tumor life and metastasis it is crucial to develop effective strategies against them. Metastatic cascade can also be directed by membrane derived vesicles specifically exosomes. Several studies show the role of exosomes in mediating cellular migration and pre-metastatic niche formation. During this chapter we wanted to explain in detail how the metastasis occur in tumor and how cancer stem cells contribute into the development of metastatic cascade and possibly suggest therapeutic approaches against cancer stem cells.

Limited effect of lymph node status on the metastatic pattern in colorectal cancer

Regional lymph node metastases in colorectal cancer (CRC) decrease outcome. Whether nodal metastases function as a biomarker, i.e. as a sign of advanced disease, or are in fact involved in the metastatic process is unclear. We evaluated metastatic patterns of CRC according to the lymph node status of the primary tumor.

A retrospective review of 1393 patients with metastatic CRC who underwent autopsy in the Netherlands was performed. Metastatic patterns of regional lymph node positive and negative CRC were compared and validated by population-based data from the Eindhoven Cancer Registry (ECR).

Patients with regional lymph node positive CRC more often developed peritoneal metastases (28% vs. 21%, p=0.003) and distant lymph node metastases (25% vs. 15%, p <0.001). Incidences of liver and lung metastases were comparable. Data from the ECR confirmed our findings regarding peritoneal (22.4% vs. 17.0%, p=0.003) and distant lymph node metastases (15.8% vs. 9.7%, p <0.001).

Regional lymph node positive CRC show a slightly different dissemination pattern, with higher rates of peritoneal and distant lymph nodes metastases. Comparable incidences of liver and lung metastases support the hypothesis that dissemination to distant organs occurs independently of lymphatic spread.

Tumor-derived exosomes in colorectal cancer progression and their clinical applications

Colorectal cancer (CRC) ranks as the third leading cause of cancer mortality in both of men and women worldwide due to its metastatic properties and resistance to current treatment. Recent studies have shown that tumor-derived exosomes play emerging roles in the development of cancer. Exosomes are nano-sized extracellular vesicles (EVs) that contain lipids, proteins, DNAs, and RNA species (mRNA, miRNA, long non-coding RNA). These exosomal cargos can be transferred locally and systemically, after taken by recipient cells, so exosomes represent a new form of intercellular communication. There is increasing evidence demonstrating that exosomes control a wide range of pathways bolstering tumor development, metastasis and drug resistance. This review provides an in-depth and timely summary of the role of exosomes in CRC. We first describe the common features and biogenesis of exosomes. We then highlight important findings that support the emerging roles of exosomes in CRC cell growth, invasion and metastasis, as well as resistance to treatment. Finally, we discuss the clinical application of exosomes as diagnostic biomarkers, in vivo drug delivery system and the potential of novel exosome-based immunotherapy for CRC.

Preclinical Modeling and Therapeutic Avenues for Cancer Metastasis to the Central Nervous System

Metastasis is the dissemination of cells from the primary tumor to other locations within the body, and continues to be the predominant cause of death among cancer patients. Metastatic progression within the adult central nervous system is 10 times more frequent than primary brain tumors. Metastases affecting the brain parenchyma and leptomeninges are associated with grave prognosis, and even after successful control of the primary tumor the median survival is a dismal 2-3 months with treatment options typically limited to palliative care. Current treatment options for brain metastases (BM) and disseminated brain tumors are scarce, and the improvement of novel targeted therapies requires a broader understanding of the biological complexity that characterizes metastatic progression. In this review, we provide insight into patterns of BM progression and leptomeningeal spread, outlining the development of clinically relevant in vivo models and their contribution to the discovery of innovative cancer therapies. In vivo models paired with manipulation of in vitro methods have expanded the tools available for investigators to develop agents that can be used to prevent or treat metastatic disease. The knowledge gained from the use of such models can ultimately lead to the prevention of metastatic dissemination and can extend patient survival by transforming a uniformly fatal systemic disease into a locally controlled and eminently more treatable one.

Lung cancer-associated brain metastasis: Molecular mechanisms and therapeutic options

BACKGROUND

Lung cancer is the most common cause of cancer-related mortality in humans. There are several reasons for this high rate of mortality, including metastasis to several organs, especially the brain. In fact, lung cancer is responsible for approximately 50% of all brain metastases, which are very difficult to manage. Understanding the cellular and molecular mechanisms underlying lung cancer-associated brain metastasis brings up novel therapeutic promises with the hope to ameliorate the severity of the disease. Here, we provide an overview of the molecular mechanisms underlying the pathogenesis of lung cancer dissemination and metastasis to the brain, as well as promising horizons for impeding lung cancer brain metastasis, including the role of cancer stem cells, the blood-brain barrier, interactions of lung cancer cells with the brain microenvironment and lung cancer-driven systemic processes, as well as the role of growth factor/receptor tyrosine kinases, cell adhesion molecules and non-coding RNAs. In addition, we provide an overview of current and novel therapeutic approaches, including radiotherapy, surgery and stereotactic radiosurgery, chemotherapy, as also targeted cancer stem cell and epithelial-mesenchymal transition (EMT)-based therapies, micro-RNA-based therapies and other small molecule or antibody-based therapies. We will also discuss the daunting potential of some combined therapies.

CONCLUSIONS

The identification of molecular mechanisms underlying lung cancer metastasis has opened up new avenues towards their eradication and provides interesting opportunities for future research aimed at the development of novel targeted therapies.

Cancer metastasis - tricks of the trade

Decades of cancer research have unraveled genetic, epigenetic and molecular pathways leading to plausible therapeutic targets; many of which hold great promise in improving clinical outcomes. Metastatic tumors become evident early on and are one of the major causes of cancer-related fatalities worldwide. This review depicts the sequential events of cancer metastasis. Genetic and epigenetic heterogeneity influences local tumor cell invasion, intravasation, survival in circulation, extravasation and colonization to distant sites. Each sequential event is associated with heterogeneous tumor microenvironment, gain of competence, unique population of cancer stem cells (CSCs), circulatory pathway, compatible niche and immune system support. A tight regulation of metastasis-promoting mechanisms and, in parallel, evading inhibitory mechanisms contribute to the severity and site of metastasis. A comprehensive understanding of tumor cell fate as an individual entity, as well as in combination with different promoting factors and associated molecular mechanisms, is anticipated in the coming years. This will enable scientists to depict design strategies for targeted cancer therapies.

Esophageal Cancer Metastases to Unexpected Sites: A Systematic Review

The most common pattern of esophageal cancer metastases (ECM) is to the lymph nodes, lung, liver, bones, adrenal glands, and brain. On the other hand, unexpected metastasis (UM) spread to uncommon sites has increasingly reported and consequently affected the pathway of diagnosis, staging, and management. Using the PubMed database, a systematic search of the following headings “Esophageal” and “Metastasis” or “Metastases” was performed, 10049 articles were identified, and the articles were included if they demonstrated unexpected ECM. 84% of cases were men with an average age of 60.7 years. EC was located in the lower third in 65%. Two-thirds of the UM originated from the lower esophagus, and the two major histological types were adenocarcinoma 40% and squamous cell carcinoma 60%. Metastases were disseminated toward five main anatomical sites: the head and neck (42%), thoracic (17%), abdomen and pelvis (25%), extremities (9%), and multiple skin and muscle metastases (7%). The EC metastases were found to be synchronous 42% and metachronous 58%, isolated in 53.5% and multiple in 46.5%. The overall survival rate was 10.2 months. Since distant metastases are responsible for most EC-related deaths, understanding of ECM dissemination patterns needs more extensive studies. These critical data are the cornerstone of optimal cancer approach and treatment.

Pathophysiology of bone metastases from solid malignancies

Bone metastases are common complications of many cancers. Among the mechanisms that set the scene for the development of bone metastases, several are shared by all forms of metastatic dissemination (pre-metastatic niche formation and chemotactic attraction of malignant cells, which invade the host tissue) and others are specific of bone tissue (homing of malignant cells to bone marrow niches and acquisition of an osteomimetic cell phenotype). After a latency period that can last several years, the malignant cells can proliferate into tumors that alter the normal bone remodeling process by inducing dysregulation of osteoblast and osteoclast function. These metastases may be lytic, characterized by major bone destruction; sclerotic, with excess bone formation; or mixed. Osteolysis occurs when the tumor cells stimulate osteoclast activity and inhibit osteoblast activity, whereas the opposite effects lead to bone sclerosis. Moreover, the mineralized bone matrix plays a major role in the formation of bone metastases, as its degradation releases growth factors and calcium that exert mitogenic effects on tumor cells. Thus, bone metastases are the site of a vicious circle in which mechanisms involved in bone resorption/formation promote tumor growth and vice versa.

Comparison of four MRI protocols for detection of extrahepatic colorectal cancer metastases

PURPOSE

To compare three magnetic resonance imaging (MRI) protocols containing diffusion-weighted imaging with background suppression (DWIBS) and one traditional protocol for detecting extrahepatic colorectal cancer metastases.

MATERIALS AND METHODS

Thirty patients with extrahepatic colorectal cancer metastases were scanned in three stations from the skull base to the upper thighs using a 1.5T MRI system with six different MRI sequences; transverse and coronal T₂ -weighted (T₂ W) turbo spin-echo (TSE), coronal short tau inversion recovery (STIR), 3D T₁ W TSE, DWIBS, and a contrast-enhanced T₁ W 3D gradient echo (GRE) sequence. The six sequences were used to build four hypothetical MRI interpretive sets which were read by two readers in consensus, blinded to prior imaging. Lesions were categorized into 13 anatomic regions. Fluorodeoxyglucose / positron emission tomography / computed tomography (FDG-PET/CT) read with full access to prior imaging and clinical records was used as the reference standard. Sensitivity, specificity, and false discovery rate (FDR) were calculated as appropriate and receiver operating characteristic (ROC) curves were constructed.

RESULTS

In all, 177 malignant lesions were detected by FDG-PET/CT and distributed in 92 out of 390 scanned anatomic regions. The sensitivity was statistically higher in two out of three sets incorporating DWIBS on a per-lesion basis (66.7%, 63.3%, and 66.7% vs. 57.6%) (P = 0.01, P = 0.11, and P = 0.01, respectively) and in all sets incorporating DWIBS on a per-region basis (75.0%, 75.0%, and 77.2 vs. 66.3%) (P = 0.04, P = 0.04, and P = 0.01, respectively). There was no difference in specificity, FDR, or AUC_ROC . There was no difference between sets containing DWIBS irrespective of the use of a contrast-enhanced sequence.

CONCLUSION

MRI sets containing DWIBS had superior sensitivity. This sensitivity was retained when omitting a contrast-enhanced sequence.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1619-1630.

Amigo2-upregulation in Tumour Cells Facilitates Their Attachment to Liver Endothelial Cells Resulting in Liver Metastases

Since liver metastasis is the main cause of death in cancer patients, we attempted to identify the driver gene involved. QRsP-11 fibrosarcoma cells were injected into the spleens of syngeneic mice to isolate tumour sub-populations that colonize the liver. Cells from liver metastatic nodules were established and subsequently injected intrasplenically for selection. After 12 cycles, the cell subline LV12 was obtained. Intravenous injection of LV12 cells produced more liver metastases than QRsP-11 cells, whereas the incidence of lung metastases was similar to that of QRsP-11 cells. LV12 cells adhered to liver-derived but not to lung-derived endothelial cells. DNA chip analysis showed that amphoterin-induced gene and open reading frame 2 (Amigo2) was overexpressed in LV12 cells. siRNA-mediated knockdown of Amigo2 expression in LV12 cells attenuated liver endothelial cell adhesion. Ex vivo imaging showed that suppression of Amigo2 in luciferase-expressing LV12 cells reduced attachment/metastasis to liver to the same level as that observed with QRsP-11 cells. Forced expression of Amigo2 in QRsP-11 cells increased liver endothelial cell adhesion and liver metastasis. Additionally, Amigo2 expression in human cancers was higher in liver metastatic lesions than in primary lesions. Thus, Amigo2 regulated tumour cell adhesion to liver endothelial cells and formation of liver metastases.

Determinants of Organotropic Metastasis

The spread of cancer from a primary tumor to distant organ sites is the most devastating aspect of malignancy. Dissemination to specific organs depends upon blood flow patterns and characteristics of the distant organ environment, such as the vascular architecture, stromal cell content, and the biochemical milieu of growth factors, signaling molecules, and metabolic substrates, which can be permissive or antagonistic to metastatic colonization. Metastatic tumor cells possess intrinsic cellular properties selected for adaptation to specific organ environments, where they co-opt growth and survival signals, undergo metabolic reprogramming, and subvert resident stromal cell activities to promote extravasation, immune evasion, angiogenesis, and overt metastatic growth. Recent work and new experimental models of metastatic organotropism are uncovering crucial details of how malignant cells metastasize to specific tissues, revealing key mediators that prepare metastatic niches in specific organs and identifying new targets that offer attractive options for therapeutic intervention.

Transfer of malignant traits as opposed to migration of cells: A novel concept to explain metastatic disease

Metastatic disease is believed to develop following dissemination of cells to target organs. Inability of this theory to effectively explain certain phenomena such as patterns of metastatic spread, late metastasis formation, different gene patterns between primary cancer and metastasis have brought forward the need for alternative models. Recent discoveries have strengthened the validity of theories supporting a humoral transfer of malignant traits as opposed to migration of malignant cells to explain metastatic disease in cancer patients. In light of this new evidence, we would like to highlight a model that offers a new perspective to explain cancer metastasis. In the system that we theorize, genetic material released by cancer cells would travel, either free or packed in exosomes, through the blood. Target cells located in organs deriving from the same embryological layer might uptake this genetic material due to expression of specific receptors. Interplay with the immune system would determine the fate of these oncofactors and would regulate their ability to circulate in the blood, integrate in the genome and be transcribed. We also hypothesize that the expression of cell membrane receptors such as integrins, to which cancer exosomes ligate might be mediated by inherited or acquired oncosuppressor mutations.

An in vivo multiplexed small-molecule screening platform

Phenotype-based small-molecule screening is a powerful method to identify molecules that regulate cellular functions. However, such screens are generally performed in vitro under conditions that do not necessarily model complex physiological conditions or disease states. Here, we use molecular cell barcoding to enable direct in vivo phenotypic screening of small-molecule libraries. The multiplexed nature of this approach allows rapid in vivo analysis of hundreds to thousands of compounds. Using this platform, we screened >700 covalent inhibitors directed toward hydrolases for their effect on pancreatic cancer metastatic seeding. We identified multiple hits and confirmed the relevant target of one compound as the lipase ABHD6. Pharmacological and genetic studies confirmed the role of this enzyme as a regulator of metastatic fitness. Our results highlight the applicability of this multiplexed screening platform for investigating complex processes in vivo.

Patterns of metastasis in colon and rectal cancer

Investigating epidemiology of metastatic colon and rectal cancer is challenging, because cancer registries seldom record metastatic sites. We used a population based approach to assess metastatic spread in colon and rectal cancers. 49,096 patients with colorectal cancer were identified from the nationwide Swedish Cancer Registry. Metastatic sites were identified from the National Patient Register and Cause of Death Register. Rectal cancer more frequently metastasized into thoracic organs (OR = 2.4) and the nervous system (1.5) and less frequently within the peritoneum (0.3). Mucinous and signet ring adenocarcinomas more frequently metastasized within the peritoneum compared with generic adenocarcinoma (3.8 [colon]/3.2 [rectum]), and less frequently into the liver (0.5/0.6). Lung metastases occurred frequently together with nervous system metastases, whereas peritoneal metastases were often listed with ovarian and pleural metastases. Thoracic metastases are almost as common as liver metastases in rectal cancer patients with a low stage at diagnosis. In colorectal cancer patients with solitary metastases the survival differed between 5 and 19 months depending on T or N stage. Metastatic patterns differ notably between colon and rectal cancers. This knowledge should help clinicians to identify patients in need for extra surveillance and gives insight to further studies on the mechanisms of metastasis.

Metastatic colonization by circulating tumour cells

Metastasis is the main cause of death in people with cancer. To colonize distant organs, circulating tumour cells must overcome many obstacles through mechanisms that we are only now starting to understand. These include infiltrating distant tissue, evading immune defences, adapting to supportive niches, surviving as latent tumour-initiating seeds and eventually breaking out to replace the host tissue. They make metastasis a highly inefficient process. However, once metastases have been established, current treatments frequently fail to provide durable responses. An improved understanding of the mechanistic determinants of such colonization is needed to better prevent and treat metastatic cancer.

Genotyping of colorectal cancer for cancer precision medicine: Results from the IPH Center for Molecular Pathology

Cancer precision medicine has opened up new avenues for the treatment of colorectal cancer (CRC). To fully realize its potential, high-throughput sequencing platforms that allow genotyping beyond KRAS need to be implemented and require performance assessment. We comprehensively analyzed first-year data of 202 consecutive formalin-fixed paraffin embedded (FFPE) CRC samples for which prospective genotyping at our institution was requested. Deep targeted genotyping was done using a semiconductor-based sequencing platform and a self-designed panel of 30 CRC-related genes. Additionally, microsatellite status (MS) was determined. Ninety-seven percent of tumor samples were suitable for sequencing and in 88% MS could be assessed. The minimal drop-out rates of 6 and 25 cases, respectively were due to too low amounts or heavy degradation of DNA. Of 557 nonsynonymous mutations, 90 (16%) have not been described in COSMIC at the time of data query. Forty-three cases (22%) had double- or triple mutations affecting a single gene. Sixty-four percent had genetic alterations influencing oncological therapy. Eight percent of patients (MSI phenotype: 6%; mutated POLE: 2%) were potentially eligible for treatment with immune checkpoint inhibitors. Of 56% of KRASwt CRC that potentially qualified for anti-EGFR treatment, 30% presented with mutations in BRAF/NRAS. Mutated PIK3CA was detected in 21%. In conclusion, we here present real-life routine diagnostics data that not only demonstrate the robustness and feasibility of deep targeted sequencing and MS-analysis of FFPE CRC samples but also contribute to the understanding of CRC genetics. Most importantly, in more than half of the patients our approach enabled the selection of the best treatment currently available. © 2016 Wiley Periodicals, Inc.

Surviving at a Distance: Organ-Specific Metastasis

The clinical manifestation of metastasis in a vital organ is the final stage of cancer progression and the main culprit of cancer-related mortality. Once established, metastasis is devastating, but only a small proportion of the cancer cells that leave a tumor succeed at infiltrating, surviving, and ultimately overtaking a distant organ. The bottlenecks that challenge cancer cells in newly invaded microenvironments are organ-specific and consequently demand distinct mechanisms for metastatic colonization. We review the metastatic traits that allow cancer cells to colonize distinct organ sites.