New Advances and Challenges of Targeting Cancer Stem Cells.

The second International Cancer Stem Cell Conference in Cleveland, Ohio, on September 20-23, 2016, convened 330 attendees from academic, industrial, and clinical organizations. It featured a debate on the concepts and challenges of the cancer stem cells (CSC) as well as CSC-centered scientific sessions on clinical trials, genetics and epigenetics, tumor microenvironment, immune suppression, metastasis, therapeutic resistance, and emerging novel concepts. The conference hosted 35 renowned speakers, 100 posters, 20 short talks, and a preconference workshop. The reported advances of CSC research and therapies fostered new collaborations across national and international borders, and inspired the next generation's young scientists. Cancer Res; 77(19); 5222-7. ©2017 AACR.

Preferential Iron Trafficking Characterizes Glioblastoma Stem-like Cells.

Glioblastomas display hierarchies with self-renewing cancer stem-like cells (CSCs). RNA sequencing and enhancer mapping revealed regulatory programs unique to CSCs causing upregulation of the iron transporter transferrin, the top differentially expressed gene compared with tissue-specific progenitors. Direct interrogation of iron uptake demonstrated that CSCs potently extract iron from the microenvironment more effectively than other tumor cells. Systematic interrogation of iron flux determined that CSCs preferentially require transferrin receptor and ferritin, two core iron regulators, to propagate and form tumors in vivo. Depleting ferritin disrupted CSC mitotic progression, through the STAT3-FoxM1 regulatory axis, revealing an iron-regulated CSC pathway. Iron is a unique, primordial metal fundamental for earliest life forms, on which CSCs have an epigenetically programmed, targetable dependence.

Chemotherapy activates cancer-associated fibroblasts to maintain colorectal cancer-initiating cells by IL-17A.

Many solid cancers display cellular hierarchies with self-renewing, tumorigenic stemlike cells, or cancer-initiating cells (CICs) at the apex. Whereas CICs often exhibit relative resistance to conventional cancer therapies, they also receive critical maintenance cues from supportive stromal elements that also respond to cytotoxic therapies. To interrogate the interplay between chemotherapy and CICs, we investigated cellular heterogeneity in human colorectal cancers. Colorectal CICs were resistant to conventional chemotherapy in cell-autonomous assays, but CIC chemoresistance was also increased by cancer-associated fibroblasts (CAFs). Comparative analysis of matched colorectal cancer specimens from patients before and after cytotoxic treatment revealed a significant increase in CAFs. Chemotherapy-treated human CAFs promoted CIC self-renewal and in vivo tumor growth associated with increased secretion of specific cytokines and chemokines, including interleukin-17A (IL-17A). Exogenous IL-17A increased CIC self-renewal and invasion, and targeting IL-17A signaling impaired CIC growth. Notably, IL-17A was overexpressed by colorectal CAFs in response to chemotherapy with expression validated directly in patient-derived specimens without culture. These data suggest that chemotherapy induces remodeling of the tumor microenvironment to support the tumor cellular hierarchy through secreted factors. Incorporating simultaneous disruption of CIC mechanisms and interplay with the tumor microenvironment could optimize therapeutic targeting of cancer.

Screening for thyroid cancer in patients with familial adenomatous polyposis.

OBJECTIVE: Clarify the incidence of thyroid cancer in patients with Familial adenomatous polyposis (FAP) in a prospective study of thyroid neck US screening. BACKGROUND: FAP is a hereditary disease predisposing to cancer in multiple organs, including the thyroid. However, routine thyroid screening for FAP patients is not generally practiced in the United States. Here, we report the initial results of a prospective thyroid cancer screening program in patients with FAP. METHODS: At the time of yearly gastrointestinal follow-up, every FAP patient in our registry was offered thyroid ultrasound (US) performed by experienced endocrine surgeons. Clinical findings related to thyroid disease were analyzed for those patients who completed screening from August 2008 to December 2009. RESULTS: : Of 192 screened FAP patients, 72 (38%) had thyroid nodules and 5 (2.6%) had thyroid cancer. Three of 5 patients with FAP and thyroid cancer were women. Four of 5 patients had the multifocal papillary type with mean size 15 mm. Clinical history and neck exam did not detect any of the 5 cancers. CONCLUSION: The incidence of thyroid cancer among FAP patients is high. Medical history and exam are inadequate to identify patients with thyroid cancer, thus thyroid screening with US is warranted.

Is the phenotype mixed or mistaken? Hereditary nonpolyposis colorectal cancer and hyperplastic polyposis syndrome.

PURPOSE: Hereditary nonpolyposis colorectal cancer is a hereditary syndrome defined by personal and family history of colorectal and other cancers. Some patients with this condition have multiple serrated polyps, which are the hallmark of hyperplastic polyposis syndrome, a rare colorectal cancer syndrome characterized by multiple hyperplastic/serrated polyps and an increased risk of colorectal cancer. We hypothesized that this may represent a unique group of patients, and this study investigates a possible association between the two syndromes. METHODS: A hereditary colorectal cancer registry was reviewed for patients who fit hereditary nonpolyposis colorectal cancer or familial colorectal cancer and hyperplastic polyposis syndrome criteria. RESULTS: Twelve patients from seven families were identified. Four families had more than one person meeting the criteria. All patients were white, and four were women. Ten of 12 patients fit Amsterdam criteria, and two were designated with familial colorectal cancer. The median cumulative number of hyperplastic polyps resected per patient was 6, half of which were located in the right colon. Seven of the 12 patients developed colorectal cancer. Ten patients had personal or family history of other cancers: prostate, breast, testicular, salivary gland, lung, and Hodgkin's disease. CONCLUSIONS: Patients meeting criteria for hereditary nonpolyposis colorectal cancer may also carry a diagnosis of hyperplastic polyposis syndrome. Possible explanations include: 1) two hereditary syndromes are present in the same patient, 2) serrated polyps are part of the phenotype of hereditary nonpolyposis colorectal cancer, or 3) hereditary nonpolyposis colorectal cancer is potentially misdiagnosed in some families who do, in fact, have hyperplastic polyposis.