Thomas G. Paulson

Learn More
Neoplasms are thought to progress to cancer through genetic instability generating cellular diversity and clonal expansions driven by selection for mutations in cancer genes. Despite advances in the study of molecular biology of cancer genes, relatively little is known about evolutionary mechanisms that drive neoplastic progression. It is unknown, for(More)
TP53 serves as a key relay for signals elicited by cellular stresses arising from diverse environmental or therapeutic insults. This relay then activates a cell cycle arrest or cell death program, depending on the stimulus and cell type. The absence of TP53 function disables the cell death or arrest programmes, thereby allowing the emergence of variants(More)
It has been hypothesized that neoplastic progression develops as a consequence of an acquired genetic instability and the subsequent evolution of clonal populations with accumulated genetic errors. Accordingly, human cancers and some premalignant lesions contain multiple genetic abnormalities not present in the normal tissues from which the neoplasms arose.(More)
Barrett's esophagus (BE) is the only known precursor to esophageal adenocarcinoma, a cancer of which the incidence has been increasing at an alarming rate in Western countries. p16(INK4a) lesions occur frequently in esophageal adenocarcinomas but their role in neoplastic progression is not well understood. We detected 9p21 loss of heterozygosity, p16 CpG(More)
There is debate in the literature over the relative importance of genetic instability and clonal expansion during progression to cancer. Barrett's esophagus is a uniquely suited model to investigate neoplastic progression prospectively because periodic endoscopic biopsy surveillance is recommended for early detection of esophageal adenocarcinoma. We(More)
Neoplastic progression is an evolutionary process characterized by genomic instability and waves of clonal expansions carrying genetic and epigenetic lesions to fixation (100% of the cell population). However, an evolutionarily neutral lesion may also reach fixation if it spreads as a hitchhiker on a selective sweep. We sought to distinguish advantageous(More)
Size changes in microsatellite sequences have been detected in many types of cancer, but the influence of this form of genetic instability on disease progression remains unclear. We determined the incidence of microsatellite instability in breast cancer by comparing PCR-amplified sequences from paraffin-embedded samples of normal and tumor tissue from(More)
All cancers are believed to arise by dynamic, stochastic somatic genomic evolution with genome instability, generation of diversity, and selection of genomic alterations that underlie multistage progression to cancer. Advanced esophageal adenocarcinomas have high levels of somatic copy number alterations. Barrett's esophagus is a risk factor for developing(More)
Amplification of genes involved in signal transduction and cell cycle control occurs in a significant fraction of human cancers. Loss of p53 function has been proposed to enable cells with gene amplification to arise spontaneously during growth in vitro. However, this conclusion derives from studies employing the UMP synthesis inhibitor(More)
Loss of heterozygosity (LOH) is a common genetic lesion found in many human neoplasms. Extending investigation of LOH to large-scale clinical and public health science studies has proven difficult because of the small size and cellular and genetic heterogeneity of human neoplasms, in addition to the challenges associated with increasing throughput. Our(More)