Metastatic Tumour Cells

Most of the cancer-related deaths are usually due to the spread of cancerous cells to distant organs. This is termed cancer metastasis and it is the last step in cancer progression. Cancer usually begins due to an overload of errors, called mutations, in a specific cell. These mutations can cause faulty signalling in the cell, leading to its uncontrolled proliferation. At this point, we have something called a tumour. This tumour is not cancerous yet.

However, the tissue is not designed to accommodate such uncontrollably dividing cells. So, as the tumour cells divide, they face heavy oxygen and nutrient deficiencies.

The solution? - The cells decide to move out to distant sites that are richer in resources.

To accomplish this, the tumour cells undergo several signalling and morphological changes. These changes allow them to hijack nearby blood vessels and travel through them to faraway sites. What you see in the image is a group of tumour cells (in blue) travelling through the blood vessels in search of ‘greener pastures’. These tumour cells can be called cancerous, and the disease is now called cancer.