Is overexpression of integrin ?v a marker of poor prognosis in colorectal cancer?

This study evaluated the effect of overexpression of integrin αv subunits in colorectal cancer prognosis (outcome).

Colorectal cancer is a form of cancer that affects the cells of the colon or the rectum. Cancer cells need an adequate supply of oxygen, nutrients and removal of waste products to grow and spread. This is usually achieved by increasing the blood supply to the tumor. Integrin αv subunits are proteins expressed on multiple cell types and contribute to angiogenesis (formation of new blood vessels) required for tumor survival and progression. A number of studies have reported an association between integrin αv expression and tumor progression or poor survival in various types of cancers. However, no study has addressed the influence of integrin αv expression on the outcome and survival of patients with colorectal cancer.

To analyze the possible correlation between expression of the integrin αv subunits and tumor progression and survival of colorectal cancer patients, this study assessed 198 colorectal cancer samples from patients who had undergone curative surgery (removal of a cancerous tumor).

High expression of integrin αv was observed in 115 out of 189 (58.1%) colorectal adenocarcinoma (the most common type of colorectal cancer) samples. It was found in 3 out of 26 (11.5%) tubular adenoma (abnormal growths that carry a high cancer risk) samples and in none of normal mucosa or hyperplastic polyp (growths considered to be non-cancerous) samples.

In addition, high-expression of integrin αv was associated with advanced colorectal cancer i.e. TMN (tumor, node, metastasis) stages III and IV. Tumor recurrence (return of the cancer) occurred in 37% of those with high integrin αv expression versus 17.3% of those with low integrin αv expression.

Overall survival and disease-free survival (period after surgery in which there is no appearance of the symptoms or effects of the disease) were shorter in patients with high levels of integrin αv expression compared to those with low expression. The 5-year overall survival rate was 61.7% and the disease-free survival rate was 62.3% in patients with high levels of integrin αv expression. The overall survival rate was 81.7% and the disease-free survival rate was 82.0% in patients with low integrin αv expression.

In summary, this study concluded that overexpression of integrin αv is associated with advanced colorectal cancer and correlates with poor disease outcome and patient survival. Integrin αv can be used as an independent marker of colorectal cancer prognosis and a therapeutic target in colorectal cancer patients.

This study involved only a small number of patients. Further large and controlled studies are necessary.