What is CUP?

Although the term 'cancer' is commonly used, it actually covers a multitude of different types of malignant diseases depending on where the disease originated in the body. When cancer cells spread to form a new tumor, it is called a secondary, or metastatic tumor (or cancer), and its cells are like those in the original tumor. This means, for example, that if breast cancer spreads (metastasizes) to the lung, the secondary tumor is made up of abnormal breast cells (not abnormal lung cells). The disease in the lung is metastatic breast cancer (not lung cancer) and requires a very different treatment of the patient than of a lung cancer patient. Therefore the primary source of the disease (e.g. breast, prostate, ovarian cancer) must be accurately identified to most effectively treat the cancer.

A metastasis is a tumor that started from a cancer cell in another part of the body. Over 10% of patients presenting to oncology units will have metastases without a clearly identifiable primary tumor. In these cases, doctors refer to the primary tumor as "unknown" and the patient is said to have cancer of unknown primary origin (CUP). Studies have shown that if simple questioning does not reveal the cancer's source (coughing up blood -'probably lung', urinating blood - 'probably bladder'), complex imaging will not either. The use of immunohistochemistry has permitted pathologists to give an identity to many of these metastases. However, the current available methods only identify the primary tumor in 20% of the CUP patients.

In cases of Cancer of Unknown Primary (CUP) or Tumor of Unknown Origin (TUO), the primary tumor is found in only 20% of the cases, even when the latest pathology and imaging techniques are used. For the majority of the CUP patients, the primary tumor remains unknown and a cancer-targeted therapy cannot be given.

Present diagnostic tools are able to detect the origin of the tumor in 80-90 % of cases which allows help physicians to make more accurate decisions about the treatment.

What is genomic profiling?
Modern cancer treatment is heavily influenced by knowledge about the primary origin of a tumor. Determining this information is obviously a crucial element of accurate tumor diagnosis. Today, many forms of primary tumor can be effectively treated, such as breast, ovarian or prostate cancer, however there are substantial variations in the most effective therapeutic approach for many tumor types. The best results are seen when cancer therapy is targeted and specific in nature.

Microarrays have been used extensively to create gene expression profiles, or genomic fingerprints, of different tumor types. By compiling a large database of these profiles and using advanced computer modelling, there has been determined a set of genes whose pattern of activity indicates the type of tissue in which they are found.