BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20260808T052359EDT-60992NRlJt@132.216.98.100 DTSTAMP:20260808T092359Z DESCRIPTION:Cancer has complex patterns of progression that includes\nconve rging as well as diverging progressional pathways. The path\nmodel of colo n cancer introduced by Vogelstein was a pioneering\ncontribution to cancer research. Since then\, several attempts have\nbeen made to obtain mathema tical models of cancer progression\,\ni.e.\, defining classes of models\, devising training algorithms\, and\napplying these to cross-sectional data . We study tree-based models\nand mixtures of such\, since they have the d esirable features of\nhaving relatively few parameters as well as being re latively easy\nto train. In this talk\, we will discuss previous work\, in cluding\nthat of Beerenwinkel et al. who provided EM-like algorithms for t he\nso-called Oncogenetic Trees and mixtures of such. We will then\nintrod uce Hidden Variable Oncogenetic Trees (HOTs) which allow for\nerrors in th e data and thereby more realistic modeling\, and we will\npresent proper E M-algorithms for the HOTs as well as HOT-mixtures.\nThe EM-algorithm for a single HOT is shown to perform very well for\nreasonable-sized data sets\ , while HOT-mixtures require data sets of\nsizes that can only be obtained with tomorrow's more cost efficient\ntechnologies. To facilitate analysis of complex cytogenetic data\nsets requiring more than one HOT\, we train parameters on a colon\ncancer (CC) data set and devise a decomposition str ategy based on\nPrincipal Component Analysis. The method so obtained is th en\nsuccessfully applied to kidney cancer (RCC).\n DTSTART:20081029T183000Z DTEND:20081029T200000Z LOCATION:McIntyre Medical Building\, CA\, QC\, Montreal\, H3G 1Y6\, 3655 pr omenade Sir William Osler SUMMARY:A Structural EM-Algorithm For a Mixture Model Capturing Cancer Prog ression URL:/channels/event/structural-em-algorithm-mixture-mo del-capturing-cancer-progression-102244 END:VEVENT END:VCALENDAR