What is cancer?

What is cancer?

Cancer starts in cells in our body. Cells are tiny building blocks that make up the organs and tissues of our bodies. They divide to make new cells in a controlled way. This is how our bodies grow, heal and repair. Cells receive signals from the body telling them when to divide and grow and when to stop growing. When a cell is no longer needed or can’t be repaired, it gets a signal to stop working and die.

Cancer develops when the normal workings of a cell go wrong and the cell becomes abnormal. The abnormal cell keeps dividing making more and more abnormal cells. These eventually form a lump (tumour). Not all lumps are cancerous. Doctors can tell if a lump is cancerous by removing a small sample of tissue or cells from it. This is called a biopsy. The doctors examine the sample under a microscope to look for cancer cells.

A lump that is not cancerous (benign) may grow but cannot spread to anywhere else in the body. It usually only causes problems if it puts pressure on nearby organs.

Diagram of cells forming a tumour
Diagram of cells forming a tumour

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A lump that is cancer (malignant) can grow into nearby tissue. Sometimes, cancer cells spread from where the cancer first started (the primary site) to other parts of the body. They can travel through the blood or lymphatic system. When the cells reach another part of the body, they may begin to grow and form another tumour. This is called a secondary cancer or a metastasis.

The lymphatic system

The lymphatic system is part of the immune system – the body’s natural defence against infection and disease. It’s made up of organs such as bone marrow, the thymus, the spleen, and lymph nodes. The lymph nodes throughout the body are connected by a network of tiny lymphatic tubes (ducts). The lymphatic system has two main roles: it helps to protect the body from infection and it drains fluid from the tissues. Mesothelioma can spread to the lymph nodes in the chest.

Lymphatic system
Lymphatic system

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Back to Understanding pleural mesothelioma

What is pleural mesothelioma?

Pleural mesothelioma is a cancer that starts in the pleura, the lining that covers the lungs and lines the ribcage.

Signs and symptoms

Symptoms of pleural mesothelioma may include fever, breathlessness, chest pain, a persistent cough and weight loss.