tailieunhanh - Báo cáo y học: " Heterogeneity in multistage carcinogenesis and mixture modeling"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: " Heterogeneity in multistage carcinogenesis and mixture modeling | Theoretical Biology and Medical Modelling BioMed Central Research Heterogeneity in multistage carcinogenesis and mixture modeling Sandro Gsteiger and Stephan Morgenthaler Address Institute of Mathematics Swiss Federal Institute of Technology Lausanne Switzerland Email Sandro Gsteiger - Stephan Morgenthaler - Corresponding author Open Access Published 21 July 2008 Received 26 October 2006 Theoretical Biology and Medical Modelling 2008 5 13 doi 1742-4682-5-13 Accepted 21 July 2008 This article is available from http content 5 1 13 2008 Gsteiger and Morgenthaler licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Carcinogenesis is commonly described as a multistage process in which stem cells are transformed into cancer cells via a series of mutations. In this article we consider extensions of the multistage carcinogenesis model by mixture modeling. This approach allows us to describe population heterogeneity in a biologically meaningful way. We focus on finite mixture models for which we prove identifiability. These models are applied to human lung cancer data from several birth cohorts. Maximum likelihood estimation does not perform well in this application due to the heavy censoring in our data. We thus use analytic graduation instead. Very good fits are achieved for models that combine a small high risk group with a large group that is quasi immune. Introduction Cancers can arise in virtually any part of the body and although there are many tissue specific properties a general multistage framework for carcinogenesis holds for most cancer types. More precisely cells must undergo an evolutionary process involving several stages and leading .