PURPOSE: Preoperative chemotherapy and radiation has become the standard of care for many patients with rectal cancer. The therapy may have toxicity and delays definitive surgery. It would therefore be desirable to identify those cancers that will not regress with preoperative therapy. We assessed a series of rectal cancers for the molecular changes of loss of heterozygosity of the APC and DCC genes, K-ras mutations, and microsatellite instability, changes that have clearly been associated with rectal carcinogenesis. METHODS AND MATERIALS: Diagnostic colonoscopic biopsies from 53 patients who received preoperative chemotherapy and radiation were assayed using polymerase chain reaction techniques followed by single-stranded conformation polymorphism and DNA sequencing. Regression of the primary tumor was evaluated using the surgically removed specimen. RESULTS: Twenty-three lesions (45%) were found to have a high degree of regression. None of the molecular changes were useful as indicators of regression. CONCLUSIONS: Recognized molecular changes critical for rectal carcinogenesis including APC and DCC loss of heterozygosity, K-ras mutations, and microsatellite instability are not useful as indicators of tumor regression following chemoradiation for rectal carcinoma.
PURPOSE: Preoperative chemotherapy and radiation has become the standard of care for many patients with rectal cancer. The therapy may have toxicity and delays definitive surgery. It would therefore be desirable to identify those cancers that will not regress with preoperative therapy. We assessed a series of rectal cancers for the molecular changes of loss of heterozygosity of the APC and DCC genes, K-ras mutations, and microsatellite instability, changes that have clearly been associated with rectal carcinogenesis. METHODS AND MATERIALS: Diagnostic colonoscopic biopsies from 53 patients who received preoperative chemotherapy and radiation were assayed using polymerase chain reaction techniques followed by single-stranded conformation polymorphism and DNA sequencing. Regression of the primary tumor was evaluated using the surgically removed specimen. RESULTS: Twenty-three lesions (45%) were found to have a high degree of regression. None of the molecular changes were useful as indicators of regression. CONCLUSIONS: Recognized molecular changes critical for rectal carcinogenesis including APC and DCC loss of heterozygosity, K-ras mutations, and microsatellite instability are not useful as indicators of tumor regression following chemoradiation for rectal carcinoma.
Authors: Melanie Spitzner; Georg Emons; Frank Kramer; Jochen Gaedcke; Margret Rave-Fränk; Jens-Gerd Scharf; Peter Burfeind; Heinz Becker; Tim Beissbarth; B Michael Ghadimi; Thomas Ried; Marian Grade Journal: Int J Radiat Oncol Biol Phys Date: 2010-11-15 Impact factor: 7.038
Authors: Cristina Bilbao; Pedro Carlos Lara; Raquel Ramírez; Luis Alberto Henríquez-Hernández; Germán Rodríguez; Orlando Falcón; Laureano León; Manuel Perucho; Bonifacio Nicolás Díaz-Chico; Juan Carlos Díaz-Chico Journal: Int J Radiat Oncol Biol Phys Date: 2010-01-01 Impact factor: 7.038
Authors: Jochen Gaedcke; Marian Grade; Klaus Jung; Markus Schirmer; Peter Jo; Christoph Obermeyer; Hendrik A Wolff; Markus K Herrmann; Tim Beissbarth; Heinz Becker; Thomas Ried; Michael Ghadimi Journal: Radiother Oncol Date: 2009-11-11 Impact factor: 6.280