Reviewing the Landscape of Cancer Survivorship: Insights from Dr. Lidia Schapira's Programs and Beyond.

The constantly escalating population of cancer survivors worldwide has prompted a focused exploration of their unique needs and experiences within the context of healthcare medicine. This review initiates its analysis inspired by Dr. Lidia Schapira's insightful keynote conference on the Survivorship 1.0 and Survivorship 2.0 Programs, shedding light on their implementation challenges and setting the stage for a comprehensive analysis of cancer survivorship initiatives. Within the transformed landscape of cancer care, patient-centric strategies embedded in cancer survivorship programs comprising vital elements such as connection, support, and education are presented. While placing cancer recurrence surveillance at the forefront, the review underlines concern regarding the potential oversight of the enduring impact on mental and physical health. Dr. Schapira's insights further extend into the exploration of mental health challenges faced by survivors, promoting an examination of diverse strategies to address these concerns. Furthermore, the discussion continues toward promising areas of research, notably Precision Medicine's role in de-escalating cancer therapies, and advocates for measures such as early cancer awareness and timely referrals to supportive services. Highlighting the significance of education, the role of online resources in enhancing the knowledge of healthcare practitioners and future generations in cancer care is then explored. The paper concludes by presenting some of the most prominent global current survivorship programs, identifying critical knowledge gaps in cancer care and projecting future developments aimed at delivering accurate and holistic care, improving the quality of life for survivors, and enhancing both mental and physical well-being. Drawing upon the insights from Dr. Schapira, this review lays the groundwork for a nuanced exploration of cancer survivorship and its multifaceted implications.

Cholangiocarcinoma Insights: Established Foundations and Cutting-Edge Innovations from Dr. James Cleary's Pioneering Research.

This paper provides insights into the conventional understanding of biliary tract malignancies, with a specific focus on cholangiocarcinoma (CCA). We then delve into the groundbreaking ideas presented by Dr. James Cleary. CCA, originating from biliary tree cells, manifests diverse subtypes contingent upon anatomical localization and differentiation status. These variants exhibit discrete genetic aberrations, yielding disparate clinical phenotypes and therapeutic modalities. Intrahepatic, perihilar, and distal CCAs intricately involve distinct segments of the biliary tree, further categorized as well-differentiated, moderately differentiated, or poorly differentiated adenocarcinomas based on their histological differentiation. Understanding the etiological factors contributing to CCA development assumes paramount importance. Stratifying these factors into two groups, those unrelated to fluke infestations (e.g., viral hepatitis and fatty liver conditions) and those associated with fluke infestations (e.g., chronic liver inflammation), facilitates predictive modeling. The epidemiology of CCA exhibits global variability, with Southeast Asia notably displaying higher incidences attributed primarily to liver fluke infestations. Jaundice resulting from bile duct obstruction constitutes a prevalent clinical manifestation of CCA, alongside symptoms like malaise, weight loss, and abdominal pain. Diagnostic challenges arise due to the symptomatic overlap with other biliary disorders. Employing comprehensive liver function tests and imaging modalities such as computed tomography assumes a pivotal role in ensuring accurate diagnosis and staging. However, the definitive confirmation of CCA necessitates a biopsy. Treatment modalities, predominantly encompassing surgical resection and radiation therapy, hold curative potential, although a considerable subset of patients is deemed unresectable upon exploration. Challenges intensify, particularly in cases classified as cancer of unknown origin, underscoring the imperative for early intervention. Advancements in genomic sequencing have revolutionized precision medicine in CCA. Distinct genomic markers, including fibroblast growth factor receptor 2 (FGFR2) alterations and isocitrate dehydrogenase 1 (IDH1) mutations, have emerged as promising therapeutic targets. FGFR2 alterations, encompassing mutations and rearrangements, play pivotal roles in oncogenesis, with FGFR inhibitors demonstrating promise despite identified resistance mechanisms. Similarly, IDH1 inhibitors face challenges with resistance, despite encouraging early clinical trial results, prompting exploration of novel irreversible inhibitors. Dr. James Cleary's illuminating discourse underscores the significance of diverse FGFR2 alterations and the potential of IDH1 inhibition in reshaping the treatment landscape for CCA. These findings unveil critical avenues for targeted therapeutic interventions, emphasizing the critical need for ongoing research to optimize outcomes in this challenging cancer subtype, incorporating innovative insights from Dr. Cleary.

Innovations in Thoracic Oncology and the Promise of Liquid Biopsies with Dr. Luis Raez.

Thoracic oncology continues to pose a great threat to human health as one of the most common forms of cancer. Liquid biopsies present a transformative approach to treating patients affected by these types of diseases by providing a less invasive genetic overview of the tumor, aiding in both diagnostic and treatment measures. The primary objective of this article is to examine the prospects of liquid biopsies in managing thoracic malignancies and to present barriers to their usage as demonstrated by Dr. Luis Raez. In examining why molecular diagnostics continue to be employed together with more traditional methods, this article presents the next steps in the clinical application of blood-based cancer screening. Future cancer diagnosis and treatment aim to prioritize circulating biomarker analyses based on their potential for the detection and monitoring of thoracic cancers. Liquid biopsies are favored thanks to their reduced invasiveness with respect to traditional treatments. The further study of clinical biomarkers and technological advancements are thus pivotal to enhance the clinical applicability of this method. In conclusion, this blood-based analysis offers a promising route by which the diagnosis, treatments, and outcomes of thoracic cancer can be improved.

The Evolving Landscape: Exploring the Future of Myelodysplastic Syndrome Treatment with Dr. Rami Komrokji.

This perspective delves into the evolving landscape of Myelodysplastic Syndrome (MDS) treatment. MDS presents a significant clinical challenge, often progressing to acute myeloid leukemia. For low-risk MDS, the emphasis is on personalized care through comprehensive risk assessment, clinical monitoring, and tailored interventions, including promising agents like erythropoiesis-stimulating agents, lenalidomide, and luspatercept, with the anticipation of an expanding therapeutic arsenal and early intervention for improved outcomes. In contrast, high-risk MDS treatment is evolving towards upfront doublet or triplet therapies with a focus on minimal residual disease (MRD) monitoring. A holistic approach integrates various modalities, including stem cell transplant and post-transplant maintenance, all guided by individual patient circumstances. Risk-adapted strategies are crucial for enhancing patient outcomes. Precision medicine for MDS treatment is budding, largely driven by Next Generation Sequencing (NGS). NGS aids in early diagnosis, prognostication, and the targeting of specific mutations, with molecular data increasingly informing treatment responses and allowing for tailored interventions. Clinical trials within homogeneous patient groups with similar molecular profiles are becoming more common, enhancing treatment precision. In conclusion, the future of MDS treatment is moving towards personalized medicine, leveraging advanced technologies like NGS and molecular insights to improve outcomes in the realm of hematological malignancies.

The Potential of Lifestyle Medicine: Strategies to Optimize Health and Well-Being in Oncology Care with Dr. Amy Comander.

The field of lifestyle medicine in cancer care and survivorship is undergoing significant transformation, presenting both challenges and opportunities. This collection of insights and reflections by an esteemed speaker aims to address critical facets of this evolving landscape and the intersection of healthcare, lifestyle, and cancer. With a focus on optimizing the health of cancer survivors, the speaker emphasizes the correlation between general population health and strategies for mitigating cancer risk. Evidence-based resources have a key role in their comprehensive insights into lifestyle changes' role in cancer prevention and survivorship. Lifestyle interventions also have a promising role in mitigating the late effects in the pediatric context. Therefore, encouraging the early adoption of healthy practices in childhood cancer survivors emerges as a pivotal strategy. Furthermore, challenges in enhancing education and access to lifestyle medicine are addressed. This highlights the importance of patient-centered communication, motivational interviewing, and personalized guidance in facilitating lifestyle changes with patients. Finally, the role of nutritionists in advising breast cancer patients to consider calorie restriction to lower IGF-1 levels is explored. This collection underscores the multifaceted nature of lifestyle medicine in cancer care, highlighting challenges, opportunities, and the transformative power of passion and curiosity in shaping healthcare careers.

Cancer and COVID-19: unravelling the immunological interplay with a review of promising therapies against severe SARS-CoV-2 for cancer patients.

Cancer patients, due to their immunocompromised status, are at an increased risk for severe SARS-CoV-2 infection. Since severe SARS-CoV-2 infection causes multiple organ damage through IL-6-mediated inflammation while stimulating hypoxia, and malignancy promotes hypoxia-induced cellular metabolic alterations leading to cell death, we propose a mechanistic interplay between both conditions that results in an upregulation of IL-6 secretion resulting in enhanced cytokine production and systemic injury. Hypoxia mediated by both conditions results in cell necrosis, dysregulation of oxidative phosphorylation, and mitochondrial dysfunction. This produces free radicals and cytokines that result in systemic inflammatory injury. Hypoxia also catalyzes the breakdown of COX-1 and 2 resulting in bronchoconstriction and pulmonary edema, which further exacerbates tissue hypoxia. Given this disease model, therapeutic options are currently being studied against severe SARS-COV-2. In this study, we review several promising therapies against severe disease supported by clinical trial evidence-including Allocetra, monoclonal antibodies (Tixagevimab-Cilgavimab), peginterferon lambda, Baricitinib, Remdesivir, Sarilumab, Tocilizumab, Anakinra, Bevacizumab, exosomes, and mesenchymal stem cells. Due to the virus's rapid adaptive evolution and diverse symptomatic manifestation, the use of combination therapies offers a promising approach to decrease systemic injury. By investing in such targeted interventions, cases of severe SARS-CoV-2 should decrease along with its associated long-term sequelae and thereby allow cancer patients to resume their treatments.

Professional Challenges for United States Hematology/Oncology Trainees during COVID-19.

COVID-19 has been devastating for patients with cancer. In this commentary, we chronicle the pandemic's downstream impacts on United States hematology/oncology trainees in terms of professional development and career advancement. These include loss of access to clinical electives and protocol workshops, delays in research approval and execution, mentor shortages due to academic burnout, and obstacles with career transitions (most notably the post-fellowship job search). While certain silver linings from the pandemic have undoubtedly emerged, continued progress against COVID-19 will be essential to fully overcome the professional challenges it has created for the future hematology/oncology workforce.

Immunotherapy in Sarcoma: Where Do Things Stand?

Early experiences with modern immunotherapy have been disappointing in trials of unselected sarcoma subtypes. However, remarkable efficacy has been observed with immune checkpoint inhibitors (ICIs) in a subset of patients, with the most promising outcomes to date in alveolar soft part sarcoma, cutaneous angiosarcoma, undifferentiated pleomorphic sarcoma (UPS), and dedifferentiated liposarcoma (dLPS). Adoptive cellular therapies targeting cancer testis antigens have shown promising activity, but only synovial sarcoma (SS) and myxoid/round cell liposarcomas reliably express these targets. The majority of sarcomas are immunologically "cold" with sparse immune infiltration, which may explain the poor response to immunotherapy. Current immunotherapy trials for sarcomas explore combination therapies with checkpoint inhibitors to overcome immune evasion and novel targets in adoptive cellular therapies. The role of tertiary lymphoid structures, PD-L1 expression, tumor mutational burden, microsatellite instability, and tumor lymphocytes as biomarkers for response are areas of active investigation. In this review, we highlight prior and ongoing clinical efforts to improve outcomes with immunotherapy and discuss the current state of understanding for biomarkers to select patients most likely to benefit from this approach.

Social Media and Professional Development for Oncology Professionals.

The use of social media continues to increase in health care and academia. Health care practice, particularly the oncologic field, is constantly changing because of new knowledge, evidence-based research, clinical trials, and government policies. Therefore, oncology trainees and professionals continue to strive to stay up-to-date with practice guidelines, research, and skills. Although social media as an educational and professional development tool is no longer completely new to medicine and has been embraced, it is still under-researched in terms of various outcomes. Social media plays several key roles in professional development and academic advancement. We reviewed the literature to evaluate how social media can be used for professional development and academic promotion of oncology professionals.

Tissue-specific Tregs in cancer metastasis: opportunities for precision immunotherapy.

Decades of advancements in immuno-oncology have enabled the development of current immunotherapies, which provide long-term treatment responses in certain metastatic cancer patients. However, cures remain infrequent, and most patients ultimately succumb to treatment-refractory metastatic disease. Recent insights suggest that tumors at certain organ sites exhibit distinctive response patterns to immunotherapy and can even reduce antitumor immunity within anatomically distant tumors, suggesting the activation of tissue-specific immune tolerogenic mechanisms in some cases of therapy resistance. Specialized immune cells known as regulatory T cells (Tregs) are present within all tissues in the body and coordinate the suppression of excessive immune activation to curb autoimmunity and maintain immune homeostasis. Despite the high volume of research on Tregs, the findings have failed to reconcile tissue-specific Treg functions in organs, such as tolerance, tissue repair, and regeneration, with their suppression of local and systemic tumor immunity in the context of immunotherapy resistance. To improve the understanding of how the tissue-specific functions of Tregs impact cancer immunotherapy, we review the specialized role of Tregs in clinically common and challenging organ sites of cancer metastasis, highlight research that describes Treg impacts on tissue-specific and systemic immune regulation in the context of immunotherapy, and summarize ongoing work reporting clinically feasible strategies that combine the specific targeting of Tregs with systemic cancer immunotherapy. Improved knowledge of Tregs in the framework of their tissue-specific biology and clinical sites of organ metastasis will enable more precise targeting of immunotherapy and have profound implications for treating patients with metastatic cancer.

Opportunities and Challenges of Observational Studies and Randomized Controlled Trials for Evaluating the Therapeutic Efficacy of COVID-19 Convalescent Plasma.

Large randomized controlled trials (RCTs) remain the gold standard for evaluating treatment efficacy. However, observational studies, including non-randomized cohort studies, as well as small RCTs have gained increasing attention especially during the SARS-CoV-2 pandemic where critical evaluation of limited therapeutic options are sought to improve patient care while awaiting results for subsequent RCTs. As the authors have previously discussed, RCTs and observational studies are complementary approaches which often appear synergistic with one another. While not all real-world studies are the same, the results of observational studies are notoriously subject to both known and unknown confounding factors. The utilization of COVID-19 Convalescent Plasma is a timely illustration of evaluating the efficacy and safety of a COVID-19 therapy given the dangerous and often lethal effects of the virus and the limited approved therapeutic options for the disease. While awaiting the results of large RCTS of convalescent plasma, serval observational cohorts and small RCTs have attempted to assess the efficacy and safety of this approach with very mixed results. Among the likely reasons for this failure to provide a definitive answer concerning the value of convalescent plasma are the many limitations inherent to addressing treatment efficacy in non-randomized studies. While such studies are often able to capture information on large numbers of individuals rapidly, it is important to understand that although larger numbers may enhance the precision of estimates provided, larger numbers, in and of themselves, do not increase the accuracy of estimates due to patient selection and other biases. At the same time, both observational studies and small RCTS are at risk for publication bias due to investigator, reviewer and editorial bias toward positive studies. In this commentary we discuss the advantages and limitations of these methodologic approaches when addressing urgently needed evidence on the effectiveness and safety of therapies in a crisis such as the COVID-19 pandemic.

Active surveillance of primary extranodal marginal zone lymphoma of bronchus-associated lymphoid tissue.

Although patients with bronchus-associated lymphoid tissue (BALT) lymphoma show an indolent clinical course, appropriate disease management at diagnosis is not well defined. This study aimed to compare 3 treatment strategies for patients with BALT lymphoma: active surveillance, systemic chemotherapy or immunotherapy at diagnosis, or complete surgical resection at diagnosis. We conducted a retrospective study of all patients with new diagnoses of marginal zone lymphoma (MZL) involving the lung who were treated at the Memorial Sloan Kettering Cancer Center between 1995 and 2017. Primary BALT lymphoma was defined as disease confined to the lungs and adjacent lymph nodes. Active surveillance was defined as a documented observation plan and ≥3 months of follow-up before initiating treatment. Overall survival (OS) and event-free survival (EFS) were compared between treatment groups. We reviewed 200 consecutive patients with MZL involving the lung; 123 met the inclusion criteria and were managed by active surveillance (47%), complete surgical resection (41%), or systemic chemotherapy or immunotherapy (11%). With a median follow-up of >60 months, surgical resection was associated with a superior EFS compared with active surveillance and systemic treatment (6-year EFS: 74% vs 65% vs 62%, respectively; P = .013). Larger lesions and thrombocytopenia were associated with shorter EFS. All groups had excellent OS at 6 years (93%), albeit with a slight superiority for surgical resection (100%) over active surveillance (91%) and systemic treatment (76%) (P = .024). BALT lymphoma is an indolent disease that can often be managed expectantly and not require therapy for many years.

The 2019-2020 Novel Coronavirus (Severe Acute Respiratory Syndrome Coronavirus 2) Pandemic: A Joint American College of Academic International Medicine-World Academic Council of Emergency Medicine Multidisciplinary COVID-19 Working Group Consensus Paper.

What started as a cluster of patients with a mysterious respiratory illness in Wuhan, China, in December 2019, was later determined to be coronavirus disease 2019 (COVID-19). The pathogen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel Betacoronavirus, was subsequently isolated as the causative agent. SARS-CoV-2 is transmitted by respiratory droplets and fomites and presents clinically with fever, fatigue, myalgias, conjunctivitis, anosmia, dysgeusia, sore throat, nasal congestion, cough, dyspnea, nausea, vomiting, and/or diarrhea. In most critical cases, symptoms can escalate into acute respiratory distress syndrome accompanied by a runaway inflammatory cytokine response and multiorgan failure. As of this article's publication date, COVID-19 has spread to approximately 200 countries and territories, with over 4.3 million infections and more than 290,000 deaths as it has escalated into a global pandemic. Public health concerns mount as the situation evolves with an increasing number of infection hotspots around the globe. New information about the virus is emerging just as rapidly. This has led to the prompt development of clinical patient risk stratification tools to aid in determining the need for testing, isolation, monitoring, ventilator support, and disposition. COVID-19 spread is rapid, including imported cases in travelers, cases among close contacts of known infected individuals, and community-acquired cases without a readily identifiable source of infection. Critical shortages of personal protective equipment and ventilators are compounding the stress on overburdened healthcare systems. The continued challenges of social distancing, containment, isolation, and surge capacity in already stressed hospitals, clinics, and emergency departments have led to a swell in technologically-assisted care delivery strategies, such as telemedicine and web-based triage. As the race to develop an effective vaccine intensifies, several clinical trials of antivirals and immune modulators are underway, though no reliable COVID-19-specific therapeutics (inclusive of some potentially effective single and multi-drug regimens) have been identified as of yet. With many nations and regions declaring a state of emergency, unprecedented quarantine, social distancing, and border closing efforts are underway. Implementation of social and physical isolation measures has caused sudden and profound economic hardship, with marked decreases in global trade and local small business activity alike, and full ramifications likely yet to be felt. Current state-of-science, mitigation strategies, possible therapies, ethical considerations for healthcare workers and policymakers, as well as lessons learned for this evolving global threat and the eventual return to a "new normal" are discussed in this article.

Potential Immunotherapeutic Targets for Hypoxia Due to COVI-Flu.

The world is currently embroiled in a pandemic of coronavirus disease 2019 (COVID-19), a respiratory illness caused by the novel betacoronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The severity of COVID-19 disease ranges from asymptomatic to fatal acute respiratory distress syndrome. In few patients, the disease undergoes phenotypic differentiation between 7 and 14 days of acute illness, either resulting in full recovery or symptom escalation. However, the mechanism of such variation is not clear, but the facts suggest that patient's immune status, comorbidities, and the systemic effects of the viral infection (potentially depending on the SARS-CoV-2 strain involved) play a key role. Subsequently, patients with the most severe symptoms tend to have poor outcomes, manifest severe hypoxia, and possess elevated levels of pro-inflammatory cytokines (including IL-1ß, IL-6, IFN-γ, and TNF-α) along with elevated levels of the anti-inflammatory cytokine IL-10, marked lymphopenia, and elevated neutrophil-to-lymphocyte ratios. Based on the available evidence, we propose a mechanism wherein SARS-CoV-2 infection induces direct organ damage while also fueling an IL-6-mediated cytokine release syndrome (CRS) and hypoxia, resulting in escalating systemic inflammation, multi-organ damage, and end-organ failure. Elevated IL-6 and hypoxia together predisposes patients to pulmonary hypertension, and the presence of asymptomatic hypoxia in COVID-19 further compounds this problem. Due to the similar downstream mediators, we discuss the potential synergistic effects and systemic ramifications of SARS-CoV-2 and influenza virus during co-infection, a phenomenon we have termed "COVI-Flu." Additionally, the differences between CRS and cytokine storm are highlighted. Finally, novel management approaches, clinical trials, and therapeutic strategies toward both SARS-CoV-2 and COVI-Flu infection are discussed, highlighting host response optimization and systemic inflammation reduction.

Chimeric antigen receptors: unleashing a new age of anti-cancer therapy.

BACKGROUND: Chimeric antigen receptors (CARs) represent a novel facet of modern day synthetic biology that exemplifies personalized medicine at work through their ability to harness and redirect a patient's immune system to fight cancer. BODY: By combining the target-specificity of antibodies to the effector capabilities of T cells, CARs have yielded high remission rates for many late staged and relapsed/refractory (r/r) hematological malignancies, including acute lymphoblastic leukemias (ALL) and Non-Hodgkin's lymphomas. Despite toxicities of cytokine release syndrome and neurotoxicity, recent studies have uncovered their underlying mechanisms and devised effective therapies to manage and possibly prevent them. In 2017, CAR T cell therapy became a reality for the general public despite the high costs, when Novartis's Kymriah, became the first product to receive FDA approval for pediatric r/r B cell ALL with Gilead's Yescarta following several months later. Although effective in hematological malignancies, CAR response has been limited in solid tumors largely attributed to the heterogeneous and immunosuppressive tumor microenvironment along tumor defense mechanisms, such as antigenic escape. CONCLUSION: Despite the current challenges of CAR T therapy, this technology is still in its infancy and its promise will continue to grow as scientists continue to develop novel approaches to enhance its efficacy. As its prevalence continues to increase, institutions and pharmaceuticals worldwide are investing in this technology in hopes of driving therapeutic innovation, while providing greater access to their respective populations through clinical trials.

New-generation taxoid SB-T-1214 inhibits stem cell-related gene expression in 3D cancer spheroids induced by purified colon tumor-initiating cells.

BACKGROUND: Growing evidence suggests that the majority of tumors are organized hierarchically, comprising a population of tumor-initiating, or cancer stem cells (CSCs) responsible for tumor development, maintenance and resistance to drugs. Previously we have shown that the CD133high/CD44high fraction of colon cancer cells is different from their bulk counterparts at the functional, morphological and genomic levels. In contrast to the majority of colon cancer cells expressing moderate levels of CD133, CD44 and CD166, cells with a high combined expression of CD133 and CD44 possessed several characteristic stem cell features, including profound self-renewal capacity in vivo and in vitro, and the ability to give rise to different cell phenotypes. The present study was undertaken for two aims: a) to determine stem cell-related genomic characteristics of floating 3D multicellular spheroids induced by CD133high/CD44high colon cancer cells; and b) to evaluate CSC-specific alterations induced by new-generation taxoid SB-T-1214. RESULTS: Selected CSC phenotype was isolated from three independent invasive colon cancer cell lines, HCT116, HT29 and DLD-1. A stem cell-specific PCR array assay (SABiosciences) revealed that colonospheres induced by purified CD133high/CD44high expressing cells display profound up-regulation of stem cell-related genes in comparison with their bulk counterparts. The FACS analysis has shown that the 3D colonospheres contained some minority cell populations with high levels of expression of Oct4, Sox2, Nanog and c-Myc, which are essential for stem cell pluripotency and self-renewal. Single administration of the SB-T-1214 at concentration 100 nM-1 microM for 48 hr not only induced growth inhibition and apoptotic cell death in these three types of colon cancer spheroids in 3D culture, but also mediated massive inhibition of the stem cell-related genes and significant down-regulation of the pluripotency gene expression. PCR array and FACS data were confirmed with western blotting. Importantly, viable cells that survived this treatment regimen were no longer able to induce secondary floating spheroids and exhibited significant morphological abnormalities. CONCLUSIONS: We report here that a new-generation taxoid SB-T-1214 possesses significant activity against colon cancer spheroids induced by and enriched with drug resistant tumorigenic CD133high/CD44high cells and efficiently inhibited expression of the majority of stem cell-related genes. Our data indicates that the previously observed long-term efficacy of SB-T-1214 against drug resistant colon tumors in vivo may be explained by the down-regulation of multiple stem cell-related genes in the tumorigenic cell population, in addition to its known efficacy as a mitotic poison against proliferating cancer cells.

Phenotypic subpopulations of metastatic colon cancer stem cells: genomic analysis.

BACKGROUND: Human cancer is characterized by high heterogeneity in gene expression, varieties of differentiation phenotypes and tumor-host interrelations. Growing evidence suggests that tumor-initiating, or cancer stem cells (CSCs), may also represent a heterogeneous population. The present study was undertaken to isolate and characterize the different phenotypic subpopulations of metastatic colon cancer and to develop a working colon CSC model for obtaining highly tumorigenic and clonogenic cells in sufficient numbers. MATERIALS AND METHODS: Different phenotypic cell subpopulations were isolated based on differential levels and patterns of expression of several stemness markers, including CD133, CD44, CD166 and CD49b. Stemness properties of isolated cells were tested by analysis of their ability to form floating colonospheres in vitro, to induce tumors in NOD/SCID mice after transplantation at relatively low cell numbers, and to produce progenitors of different phenotypes. RESULTS: The metastatic colon cancer HCT116 cell line, which expressed a majority of known CSC markers, closely resembling the patterns of expression in exfoliated peritoneal cells from several metastatic colon cancer patients, was selected as a reference material. Genome-wide microarray analysis (Affymetrix; DAVID) of CD133(high) CSC-enriched versus CSC-depleted cell populations revealed 4,351 differentially expressed genes with an overrepresentation of those responsible for apoptosis resistance, regulation of cell cycle, proliferation, stemness and developmental pathways. Simultaneous analysis of 84 stem cell- and metastasis-related genes with corresponding PCR arrays identified genes differentially expressed in several colon CSC phenotypic populations versus bulk tumor cells, and in relation to each other. It was found that colonospheres induced by tumorigenic cells with the highest expression of CD133 and those which were induced by CD133/CD44-negative cells possessed profoundly different stem cell-related gene expression profiles. CONCLUSION: The proposed approaches allow for reliable isolation and propagation of highly tumorigenic and clonogenic cells of different phenotypes. Genomic analysis of several candidate CSC phenotypic populations may contribute to the identification of novel targets for colon cancer stem cell-targeted drug development and treatment.