2010 to 2012
Developing reliable biomarkers for predicting the risk of metastasis/recurrence for individual colorectal cancer patients
Dr. Roberta Pang
The University of Hong Kong
Colorectal cancer is a leading cancer killer worldwide, claiming about 500,000 lives every year. In Hong Kong, it is the second most common of all cancers with over 4,000 new cases annually. With recent rapid increase in incidence, colorectal cancer is likely to become the most common cancer in Hong Kong in the next few years.
Colorectal cancer tends to metastasize (or spread) to the liver, and liver metastasis is a major cause of death of colorectal cancer. More over, patients who have their liver metastases removed by surgery often see their cancer return to the remnant liver, causing recurrence of liver metastasis. There is still hope. If liver metastatic tumor can be surgically removed at an early stage, 40% of the patients can live 5 years or longer after their surgery. The current pressing need is to develop reliable biomarkers that can be used to predict the risk of metastasis/recurrence for individual colorectal cancer patients. With such biomarkers, more patients’ liver metastases can be detected at an early stage when surgical removal of the metastatic tumor is still possible. By using these biomarkers, appropriate treatment strategies can also be developed by doctors for individual patient based on their own risk of cancer recurrence, further improving patients’ chance of survival.
Currently, there is no reliable biomarker available for clinical doctors to predict, with high confidence, a colorectal cancer patient’s risk of metastasis or recurrence. This has led cancer researchers to take a deep look at specific aspects of tumor biology and genetics to find reliable and accurate predictive biomarkers, and Dr. Roberta Pang from the University of Hong Kong is a pioneering leader in this field.
Cancer stem cells (CSCs) are cancer cells found within a tumor that possess the ability to give rise to all cell types. Dr. Pang’s research team recently discovered that a subset of cancer stem cells called CD26+ CSCs, is responsible for the development of metastasis in human colorectal cancer. Their breakthrough discovery points CD26+ CSCs as a promising new biomarker for predicting liver metastasis/recurrence in colorectal cancer patients.
Furthermore, Dr. Pang has shown in tumor models that it is possible to detect CD26+ CSCs with a simple blood test. This represents an intriguing and minimally invasive approach that is highly preferable in clinical settings.
With funding from AFCR, the team will further validate their findings in humans. Dr. Pang’s newly proposed research project to AFCR involves monitoring the level of circulating CD26+ CSCs in patients before and after surgical removal of their primary and/or metastatic tumors. It is expected that a resurge of circulating CD26+ CSCs may be observed in patients who will develop metastasis or cancer recurrence.
Findings coming out of Dr. Pang’s proposed study will have significant implications for the diagnosis and treatment of colorectal cancer. Identifying those with highest risk of metastasis is an important area of clinical investigation because these patients stand to gain the most from aggressive systemic therapy. Moreover, Dr. Pang’s research project will further validate CSCs as potential targets for the development of novel therapeutic strategies that may renew hope for colorectal cancer patients.