Research Article

Origins of lymphatic and distant metastases in human colorectal cancer

See allHide authors and affiliations

Science  07 Jul 2017:
Vol. 357, Issue 6346, pp. 55-60
DOI: 10.1126/science.aai8515

You are currently viewing the abstract.

View Full Text

Metastases undergo reconstruction

Cancer cells from primary tumors can migrate to regional lymph nodes and distant organs. The prevailing model in oncology is that lymph node metastases give rise to distant metastases. This “sequential progression model” is the rationale for surgical removal of tumor-draining lymph nodes. Naxerova et al. used phylogenetic methods to reconstruct the evolutionary relationship of primary tumors, lymph node metastases, and distant metastases in 17 patients with colorectal cancer (see the Perspective by Markowitz). The sequential progression model applied to only one-third of the patients. In the other two-thirds, distant metastases and lymph node metastases originated from independent subclones within the primary tumor.

Science, this issue p. 55; see also p. 35

Abstract

The spread of cancer cells from primary tumors to regional lymph nodes is often associated with reduced survival. One prevailing model to explain this association posits that fatal, distant metastases are seeded by lymph node metastases. This view provides a mechanistic basis for the TNM staging system and is the rationale for surgical resection of tumor-draining lymph nodes. Here we examine the evolutionary relationship between primary tumor, lymph node, and distant metastases in human colorectal cancer. Studying 213 archival biopsy samples from 17 patients, we used somatic variants in hypermutable DNA regions to reconstruct high-confidence phylogenetic trees. We found that in 65% of cases, lymphatic and distant metastases arose from independent subclones in the primary tumor, whereas in 35% of cases they shared common subclonal origin. Therefore, two different lineage relationships between lymphatic and distant metastases exist in colorectal cancer.

View Full Text