Researchers have been studying metastasis for more than 100 years, and only recently have we gained insight into the mechanisms by which metastatic cells arise from primary tumours and the reasons that certain tumour types tend to metastasize to specific organs. Stephen Paget's 1889 proposal that metastasis depends on cross-talk between selected cancer cells (the 'seeds') and specific organ microenvironments (the 'soil') still holds forth today. It is now known that the potential of a tumour cell to metastasize depends on its interactions with the homeostatic factors that promote tumour-cell growth, survival, angiogenesis, invasion and metastasis. How has this field developed over the past century, and what major breakthroughs are most likely to lead to effective therapeutic approaches?
From the pioneering work with acute transforming retroviruses to the current post-genomic era, RAS genes have always been at the leading edge of signal transduction and molecular oncology. Yet, a complete understanding of RAS function and dysfunction - mainly in human cancer - is still to come. The knowledge that has accumulated since their discovery 30 years ago has, however, been remarkable, and should pave the way for not only solving the outstanding issues regarding RAS biology, but also for developing efficacious drugs that could have a significant impact on cancer treatment.
Background Benign metastasizing leiomyomas (BMLs) represent the extrauterine spread of a benign uterine process. Pulmonary BMLs are the most common example of distant spread of uterine leiomyomas and are usually found incidentally in premenopausal women. The rarity of BMLs accounts for the limited literature that currently exists regarding their underlying pathophysiology, disease course, and management. Methods A retrospective analysis was performed of all BML cases diagnosed and managed at Brigham and Women’s Hospital during a 22-year period. The demographic and clinical characteristics of these patients were compared with a PubMed-derived cohort of BML cases reported since 2006. Results Benign metastasizing leiomyoma tumors were identified in 10 Brigham and Women’s Hospital patients, whereas 57 cases were reported in the literature. The average age at diagnosis was 54.1 and 46.7 years, respectively. Mean interval time from a pertinent gynecologic procedure to BML diagnosis was 23 years at Brigham and Women’s Hospital. All patients demonstrated positivity for actin, desmin, and estrogen/progesterone receptors, confirming the diagnosis of uterine leiomyomas. Management primarily consisted of diagnostic resection with subsequent observation with or without hormonal suppression for residual pulmonary nodules. Progression of residual BMLs was noticed in 30% and 8.3% of Brigham and Women’s Hospital and literature patients, respectively, when follow-up was reported. One patient in our series required further surgical management. Conclusions Benign metastasizing leiomyomas are a rare cause of pulmonary nodules. They likely represent a clonal spread of uterine leiomyomas to the lungs. Management includes pathologic diagnosis with long-term surveillance with or without hormonal manipulation.
Cardiovascular disease and cancer are ranked as the first and second leading causes of death in the United States and in most industrialized countries. Regular consumption of fruit and vegetables is associated with reduced risks of cancer, cardiovascular disease, stroke, Alzheimer disease, cataracts, and some of the functional declines associated with aging. Prevention is a more effective strategy than is treatment of chronic diseases. Functional foods that contain significant amounts of bioactive components may provide desirable health benefits beyond basic nutrition and play important roles in the prevention of chronic diseases. The key question is whether a purified phytochemical has the same health benefit as does the whole food or mixture of foods in which the phytochemical is present. Our group found, for example, that the vitamin C in apples with skin accounts for only 0.4% of the total antioxidant activity, suggesting that most of the antioxidant activity of fruit and vegetables may come from phenolics and flavonoids in apples. We propose that the additive and synergistic effects of phytochemicals in fruit and vegetables are responsible for their potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruit and vegetables is attributed to the complex mixture of phytochemicals present in whole foods.
When the cell-surface receptor Notch interacts with a ligand (e.g., Delta), its intracellular domain is cleaved and travels to the nucleus to regulate transcription. This influences cell division, fate, and death in metazoans.
Worldwide, an estimated 2 billion people live primarily on a meat-based diet, while an estimated 4 billion live primarily on a plant-based diet. The US food production system uses about 50% of the total US land area, 80% of the fresh water, and 17% of the fossil energy used in the country. The heavy dependence on fossil energy suggests that the US food system, whether meat-based or plant-based, is not sustainable. The use of land and energy resources devoted to an average meat-based diet compared with a lactoovovegetarian (plant-based) diet is analyzed in this report. In both diets, the daily quantity of calories consumed are kept constant at about 3533 kcal per person. The meat-based food system requires more energy, land, and water resources than the lactoovovegetarian diet. In this limited sense, the lactoovovegetarian diet is more sustainable than the average American meat-based diet.
Background: Diets rich in fruit and vegetables have been recommended for preventing cancer. The evidence supporting this recommendation is based on observational studies, although results of several prospective studies have cast some doubts on whether fruit and vegetables are associated with cancer risk reduction. Objective: We sought to summarize evidence from case-control and prospective studies on fruit and vegetable intake and cancer risk with a meta-analytic approach. Design: Published case-control and cohort studies that reported on total vegetable and fruit intake and risk of cancer of several sites were included. Relative risks were estimated by using linear logistic regression models. Results: Case-control studies overall support a significant reduction in the risks of cancers of the esophagus, lung, stomach, and colorectum associated with both fruit and vegetables; breast cancer is associated with vegetables but not with fruit; and bladder cancer is associated with fruit but not with vegetables. The overall relative risk estimates from cohort studies suggest a protective effect of both fruit and vegetables for most cancer sites considered, but the risk reduction is significant only for cancers of the lung and bladder and only for fruit. Conclusions: Prospective studies provide weaker evidence than do case-control studies of the association of fruit and vegetable consumption with reduced cancer risk. The discrepancies may be related to recall and selection biases in case-control studies. In contrast, the association may have been underestimated in prospective studies because of the combined effects of imprecise dietary measurements and limited variability of dietary intakes within each cohort.
Evidence from prospective cohort studies indicates that a high consumption of plant-based foods such as fruit and vegetables, nuts, and whole grains is associated with a significantly lower risk of coronary artery disease and stroke. The protective effects of these foods are probably mediated through multiple beneficial nutrients contained in these foods, including mono- and polyunsaturated fatty acids, n-3 fatty acids, antioxidant vitamins, minerals, phytochemicals, fiber, and plant protein. In dietary practice, healthy plant-based diets do not necessarily have to be low in fat. Instead, these diets should include unsaturated fats as the predominant form of dietary fat (eg, fats from natural liquid vegetable oils and nuts), whole grains as the main form of carbohydrate, an abundance of fruit and vegetables, and adequate n-3 fatty acids. Such diets, which also have many other health benefits, deserve more emphasis in dietary recommendations to prevent chronic diseases.