Single Cell Sequencing Suggests Tumors Evolve in Staccato-Like Bursts

A new method of analyzing cancerous tumors developed by scientists at Cold Spring Harbor Laboratory (CSHL) suggests that tumors may not evolve gradually, but rather in punctuated or staccato-like bursts. It is a finding that has already shed new light on the process of tumor growth and metastasis, and may help in the development of new methods to clinically evaluate tumors. The new analytic method, devised by CSHL Professor Michael Wigler and colleagues, features a process called single cell sequencing (SNS), which enables accurate quantification of genomic copy number within a single cell nucleus. In cancer, portions of the genome are amplified or deleted, giving rise to extra or missing copies of key genes and interfering with mechanisms that normally control cell growth. In a study published online on March 13, 2011, in the journal Nature, "we demonstrated that we can obtain accurate and high-resolution copy number profiles by sequencing a single cell from a cancerous tumor," said Dr. Wigler, "and that by examining multiple cells from the same cancer, we can make inferences about how the cancer evolved and spread." The CSHL team also included Professor W. Richard McCombie, Assistant Professor Alex Krasnitz and Research Professor James Hicks. Nicholas Navin, the paper's first author, was a graduate student while pursuing the research at CSHL and is now Assistant Professor at the MD Anderson Cancer Center in Texas. It has been very difficult for scientists to translate their growing ability to classify tumors at the molecular level into methods and tests that can be used in the clinic to analyze tumors in actual patients.