In a nutshell
In this meta-analysis (an analysis of data combined from several similar trials), researchers examined the presence of CD166 in cancer cells and its relationship with disease prognosis. The relationship between CD166 and tumor size, stage, and patient survival after diagnosis was analyzed.
Some background
In order to devise the best treatment strategy for patients, it is important for physicians to understand how aggressive a cancer might be. Researchers can often predict how aggressive a cancer is based on which molecules are found on or within the cancer cells. These are often referred to as cellular markers or clusters of differentiation (CD's). CD166, for example, is a protein that is sometimes found inside, or on the surface of, cancer cells of the digestive tract (esophageal, gastric, pancreatic, and colorectal cancers). However, recent studies have shown conflicting results regarding the effect of this protein on patient survival and cancer characteristics.
Methods & findings
Researchers analyzed 9 studies examining CD166 in digestive cancers, including a total of 2,553 patients. 56% of patients were found to be CD166-positive. Among most cancer types, the presence of CD166 within cancer cells was more likely to occur in small tumors than larger tumors. However, in colorectal cancer, CD166 was more likely to occur in larger tumors. Among all cancers, including colorectal cancer, the presence of CD166 was linked to the spread of the cancer into nearby lymph nodes.
The overall survival rate after 5 years were not significantly different between CD166-positive and CD166-negative patients. However, when CD166 was found both inside the cells (in the cellular cytoplasm), and on the cell surface (on the cellular membrane), the risk for death within 5 years was increased by 47%.
The bottom line
This analysis concluded that for colorectal cancer CD166 is associated with larger tumor size and lymph node involvement. The effect of CD166 on survival appears to be dependent on the location of CD166 within the cancer cells.
The fine print
This analysis included several trials employing different staining methods to detect CD166. This may have created some bias in the reported results, however the probability of this is small.
What’s next?
Consult with your physician regarding cellular markers and their ability to predict disease progression and prognosis.
Published By :
PLOS ONE
Date :
Aug 05, 2013
