Tumor profiling is emerging in many malignancies and some tests are clinically available, such as MammaPrint and Oncotype DX. For example, Oncotype DX uses gene expression data to quantify recurrence risk in node-negative, ER-positive breast cancer.
A new area of research in cancer prognosis involves the study of ribonucleic acid (RNA) gene products called microRNAs or miRNAs. MicroRNAs are small, non-protein-coding RNA gene products that contribute to regulation of gene expression. Researchers have investigated use of miRNAs as cancer-related biomarkers in hepatocellular carcinoma (HCC). HCC is an aggressive type of cancer that has a high incidence of metastasis and recurrence after surgery. The miRNA expression profiles of both cancerous and noncancerous specimens were examined in a group of patients who had HCC. Results indicate that miRNA expression profiles may help to identify HCC patients who are most likely to experience metastases and recurrence of their cancer. The researchers suggest that conducting a functional analysis of these microarrays may help scientists to better understand HCC metastasis.
Selection of Treatment
Human genome research is leading towards a more individualized approach to the use of pharmaceuticals. Pharmacogenomics takes an individual's genetic makeup and uses this information to inform the selection of the drug and drug doses that will work best for that person. This area of research and treatment combines the science of pharmacology, or how drugs work, with the science of genomics.
Treatment of cancer using the science of pharmacogenomics is advancing rapidly. For example, clinical research studies have shown that individuals with metastatic colorectal cancer who have specific mutations in the gene called KRAS benefit from anti-epidermal growth factor receptor (EGFR) antibody therapy with cetuximab(Drug information on cetuximab) (Erbitux). The American Society of Clinical Oncology now recommends that all patients with metastatic colorectal cancer who are candidates for anti-EGFR antibody therapy have their tumor tested for KRAS mutations. Patients found to have a KRAS mutation in certain areas of the gene called codon 12 or 13 do not benefit from cetuximab as a part of their treatment and therefore are not recommended to receive this agent. The US Food and Drug Administration recently approved revisions to the US prescription information for cetuximab in the treatment of patients who have EGFR-expressing metastatic colorectal cancer. Labeling information for cetuximab now states that retrospective studies of metastatic or advanced colorectal cancers have shown no treatment benefit for use of cetuximab in patients whose tumors had KRAS mutations in codon 12 or 13, and therefore cetuximab is not recommended in those patients.
Another approach to personalized healthcare and cancer therapy involves targeted therapies. This therapeutic approach involves cancer drugs that specifically target genetic changes in certain malignancies. Treatment of breast cancer is an example of this approach. Trastuzumab(Drug information on trastuzumab) (Herceptin) is a monoclonal antibody that binds to human epidermal growth factor receptor 2, called HER2. Monoclonal antibodies are created in the laboratory and can locate and bind to substances in the body, including cancer cells. This therapy has been found to work for women whose tumors have a specific genetic profile that causes overproduction of HER2, a protein found in some types of cancer cells, including breast and ovarian cancer. Standard practice now involves testing breast cancer tumors for ERBB2 gene expression. Those with HER2-positive breast cancer are candidates for therapy with trastuzumab.