ALL stands for Acute Lymphoblastic Leukaemia (also known as Acute Lymphocytic Leukaemia or Acute Lymphoid Leukaemia). ALL is a form of blood cancer affecting the lymphocytes, a type of blood cell (Figure 1) that fights infection.
Adult ALL is classified as a rare disease and accounts for only ~20% of adult leukaemia cases.
Normally, lymphocytes have a set lifespan. They grow, multiply and die in a controlled manner after which they are replaced by a new cell.
In ALL, a single lymphocyte cell in the bone marrow is mutated or changed allowing it to grow and divide in a rapid and uncontrolled manner. The resulting 'abnormal' cells are usually 'immature' and known as (lympho-) blast cells which is why the condition is called acute lymphoblastic leukaemia.
These abnormal cells fill the bone marrow and eventually affect its ability to produce all types of red and white blood cells causing:
The progression of ALL (Figure 2) can be very rapid (known as 'acute'). Mutated cells can spread into different tissues including the fluid in the spine (cerebrospinal fluid) which is the reason why early diagnosis and treatment is so important.
White blood cells are the immune cells of the body that fight against infections. There are two major groups of white blood cell, lymphocytes and phagocytes:
All of the white blood cells are produced by the bone marrow, the soft tissue inside the long bones of the body. The bone marrow is also responsible for producing red blood cells that carry oxygen around the body and platelets which are small pieces of cells that stop bleeding by blocking damaged blood vessels.
No one really knows what causes ALL. Exposure to high-dose radiation is the only clearly identified risk factor. Other less clear risk factors include; being white, male, aged older than 70 years and having certain genetic disorders such as Down's syndrome.
There are many different types of ALL that can be distinguished by the type of cell (such as a B cell [Figure 3]) involved and genetic factors (such as chromosome abnormalities [see 'What is a chromosome?' and 'What is the Philadelphia chromosome?']. The majority of adult ALL cases begin with the mutation of an immature B cell (75% incidence), with mutations in T cells (20% incidence) or more mature B cells (5% incidence) occurring less frequently. New genes are constantly being discovered and treatments are advancing allowing doctors to personalise treatment to attack the abnormal ALL cells specifically in each patient [see 'What factors will affect my treatment and prognosis'].
Chromosomes are the structures that hold our genetic information in the form of DNA (deoxyribonucleic acid), the building blocks of life. Chromosomes are found within cells contained in a structure called the nucleus. Humans have 23 pairs of chromosomes (one of each pair comes from each parent). Chromosome abnormalities can be associated with certain types of ALL; your doctor will specifically tailor your treatment to fit the type of ALL you have.
The Philadelphia chromosome was identified in another type of leukaemia called chronic myelogenous leukaemia (CML) but is also found in around 20% of ALL cases. It has traditionally been considered as a marker of poorer prognosis, although the availability of newer drugs such as imatinib mesylate has helped to improve patient outcomes.
The Philadelphia chromosome is a genetic abnormality that involves the movement of genetic material between chromosomes 9 and 22.
If you have an identical twin, they are at an elevated risk of also developing ALL and should consult a doctor to monitor their condition. There is no direct evidence demonstrating an increased risk for siblings (non-twins) or children of a patient with ALL. However, if you are concerned and have a history of ALL in your family please consult your doctor who should be able to help.
No, you are not contagious. ALL is not an infectious disease and cannot be caught by people you come into contact with.
 Cancer Treatment Centers of America – http://www.cancercenter.com
 Leukaemia Research Foundation – http://www.lrf.org.uk
 Souhami R and Tobias J. Cancer and its management. Wiley-Blackwell 2005, 5th edition
EUSA Pharma is not responsible for the content of external internet sites