Una cosa por otra: H. pilory protects children from asthma

H. pilory es una bacteria que en humanos puede causar gastritis y úlceras, sin embargo, recientemente se ha encontrado que tanto en adultos como en niños las presencia de H. pilory disminuye el riesgo de asma. Esto nos lleva a pensar que al erradicar esta bacteria estamos dejando más susceptible a la población humana de desarrollar asma

"Among teens and children ages 3 to 19 years, carriers of H. pylori were 25 percent less likely to have asthma."

The impact was even more potent among children ages 3 to 13: they were 59 percent less likely to have asthma if they carried the bacterium, the researchers report. H. pylori carriers in teens and children were also 40 percent less likely to have hay fever and associated allergies such as eczema or rash."

"These results, which follow on from similar findings in adults published by the same authors last year, are based on an analysis of data gathered from 7,412 participants in the fourth National Health and Nutrition Survey (NHANES IV) conducted from 1999 to 2000 by the National Center for Health Statistics"

"Asthma has been rising steadily for the past half-century. Meanwhile H. pylori, once nearly universal in humans, has been slowly disappearing from developed countries over the past century due to increased antibiotic use, which kills off the bacteria, and cleaner water and homes"

http://www.sciencedaily.com/releases/2008/07/080715071419.htm

Cell lineage analysis of a mouse tumor.

1: Cancer Res. 2008 Jul 15;68(14):5924-31.

Cell lineage analysis of a mouse tumor.

Frumkin D, Wasserstrom A, Itzkovitz S, Stern T, Harmelin A, Eilam R, Rechavi G, Shapiro E.

Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel.

Revealing the lineage relations among cancer cells can shed light on tumor growth patterns and metastasis formation, yet cell lineages have been difficult to come by in the absence of a suitable method. We previously developed a method for reconstructing cell lineage trees from genomic variability caused by somatic mutations. Here, we apply the method to cancer and reconstruct, for the first time, a lineage tree of neoplastic and adjacent normal cells obtained by laser microdissection from tissue sections of a mouse lymphoma. Analysis of the reconstructed tree reveals that the tumor initiated from a single founder cell, approximately 5 months before diagnosis, that the tumor grew in a physically coherent manner, and that the average number of cell divisions accumulated in cancerous cells was almost twice than in adjacent normal lung epithelial cells but slightly less than the expected figure for normal B lymphocytes. The cells were also genotyped at the TP53 locus, and neoplastic cells were found to share a common mutation, which was most likely present in a heterozygous state. Our work shows that the ability to obtain data regarding the physical appearance, precise anatomic position, genotypic profile, and lineage position of single cells may be useful for investigating cancer development, progression, and interaction with the microenvironment.

Human Breast cancer cells traced to transplanted stem cells on humans

Human Breast cancer cells traced to transplanted stem cells on humans

Martha Kerr Reuters Health Last Modified: June 26, 2008

Last Updated: 2008-06-26 16:24:49 -0400 (Reuters Health) NEW YORK (Reuters Health) - Stem cells can give rise to both breast cancer cells and the cells of the tumor microenvironment. Furthermore, stem cells transplanted from a donor can be the source of breast cancer in a transplant recipient. "This is a whole new way of thinking about stem cells and cancer," Dr. Sanford H. Barsky told Reuters Health about research he is presenting at the Department of Defense's Era of Hope Breast Cancer Research meeting that has just convened in Baltimore, Maryland. Dr. Barsky, of The Ohio State University in Columbus, and colleagues conducted two phases of study. One phase was a search of a bone marrow and organ transplant registry, in which "we noticed the origins of some cancers were from the donor organ," Dr. Barsky said. "Cancer-promoting donor stem cells lodged in different sites in the recipients and developed." In the second phase of their research, conducted in mice, the Ohio team tagged bone marrow cells before transplantation. The researchers were able to observe that "breast cancer doesn't just arise in breast tissue and everything that contributes to the breast cancer microenvironment doesn't reside only in the breast." "Invasive breast cancers reflect the presence of both cancer-promoting as well as cancer-initiating stem cells derived from ectopic locations," Dr. Barsky explained. "It appears that breast cancers and the tumors' microenvironment both arise from stem cells." "Inflammatory breast cancers form from emboli in vascular channels, and these channels form the microenvironment. Both arise from donor stem cells and there is cross-talk between them," the researcher added. In the abstract for their presentation, the investigators write, "These emboli, which were resistant to chemotherapy, exhibited a prominent stem cell-like phenotype...suggesting that the lymphovascular tumor emboli, like the human embryonal blastocyst, are derived from stem cells locked in self-renewal... some of the endothelial cells which lined the channels containing the tumor emboli exhibited evidence of bone marrow origin." "This shows that we may be able to turn off cancer cells at the level of the stem cell," Dr. Barsky said. "If we can't stop the stem cells, then maybe we could replace the cancer cells with normal cells." "Breast cancer is really a rare disease at the cellular level, despite the fact that it is fairly common on a population basis...and stem cells are rare in the breast," Dr. Barsky noted. "Our research could lead to a way of tagging cancer cells from their point of origin and may provide a new method of drug delivery." http://www.oncolink.com/resources/article.cfm?c=3&s=8&ss=23&Year=2008&Month=06&id=15400

Is Tumor Growth Sustained by Rare Cancer Stem Cells or Dominant Clones?

les recomiendo que lean este artículo de revisión de Cancer Research:

A key issue for cancer biology and therapy is whether the relentless growth of a tumor is driven by a substantial proportion of its cells or exclusively by a rare subpopulation, commonly termed "cancer stem cells." Support for the cancer stem cell model has been stimulated by experiments in which human tumor cells were transplanted into immunodeficient mice. Most notably, in human acute myeloid leukemia, only a minute proportion of the cells, displaying a defined phenotype, could seed leukemia in mice. Xenotransplantation, however, may fail to reveal many tumor growth–sustaining cells because the foreign microenvironment precludes essential interactions with support cells. In studies that instead have transplanted mouse leukemias and lymphomas into syngeneic animals, most of the tumors seem to be maintained by the dominant cell population, and only a few types of mouse leukemia seem to be sustained by a minor tumor growth–sustaining subpopulation. The collective evidence suggests that various tumors may span the spectrum between the extremes represented by the two models. If tumor growth can indeed be sustained either by rare cancer stem cells or dominant clones or both, as current evidence suggests, curative therapy for many types of tumors will most likely require targeting all the tumor cell populations. [Cancer Res 2008;68(11):4018–21]

http://canreviews.aacrjournals.org/cgi/reprint/canres;68/11/4018