Nucleic acid based techniques for the detection of rare cancer cells in clinical samples.
Solid tumors evolve from cells which have lost control functions safeguarding their genomic integrity by mutation within specific genes. Consequently, proliferating cells within a tumor differ slightly from generation to generation. This permits the continuous production of new and subsequent selection of the best adapted cells, which retain this capacity of self-evolution. The threat of neoplastic diseases is due to the clinical experience, that surgical resection of all cells with this potential for autonomous evolution is often not achievable, since they were spread to distant non-resectable sites in the organism before diagnosis and surgical removal of the primary tumor and might later grow out as metastatic lesion. Lack of diagnostic techniques to detect small preneoplastic lesions as well as single spread cancer cells often causes delayed diagnosis when curative therapy is no longer achievable. Recent advances in characterizing the molecular basis of genomic instability, identifying specific gatekeeper mutations and their functional consequences in neoplastic cells now permit the development of new highly sensitive tests to identify preneoplastic lesions as well as spread single cancer cells. These techniques carry a tremendous potential for simple cost effective cancer early detection and screening assays as well as for diagnostic applications to identify spread cancer cells. Thus, they most likely will soon guide indication for surgical and adjuvant therapy protocols for patients with preneoplastic or neoplastic lesions. However, due to the complexity of the assays and the great variety of technical aspects involved almost all diagnostic applications are not yet standardized. This poses significant problems for quality control as well as inter-laboratory comparability of the results and underlines the urgent demand for well controlled collaborative efforts to evaluate indications and diagnostic standards for these assays. Here, the theoretical background, basic principles and some diagnostic applications of these new tests are reviewed.
von Knebel Doeberitz
M
M
Department of Surgery, University of Heidelberg, Germany. knebel@med.uni-heidelberg.de
Lacroix
J
J
D000818:Animals; D002455:Cell Division / Q000235:genetics; D004273:DNA, Neoplasm / Q000032:analysis* / Q000235:genetics; D006801:Humans; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats; D009369:Neoplasms / Q000235:genetics* / Q000473:pathology*; D009693:Nucleic Acid Hybridization; D017354:Point Mutation; D012334:RNA, Neoplasm / Q000032:analysis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D004273:DNA, Neoplasm; D012334:RNA, Neoplasm