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Blood Cancer


Image is courtesy of Biomed Central.


Blood cancer classifications


Image is courtesy of WebMD.


There are a few different types of cancer associated with malfunctioning white blood cells, as seen in the flowchart above. Leukemia, Lymphoma, and Myeloma may be easily confused with one another, as they all disrupt the immune system and cause the body to be not able to fight off foreign invaders. You may have also heard of the term Hemophilia, which is not a type of cancer, but it is the disorder where blood doesn’t clot properly, causing open wounds to be very dangerous. This article will focus on blood cancers. Please visit this link to read more about hemophilia.


Leukemia


Leukemia is when the stem cells in the bone marrow that are supposed to make healthy blood cells stop making healthy blood cells. Instead, the bone marrow makes excessive amounts of white blood cells that cannot fight off infections and some red blood cells that don’t carry enough oxygen. As leukemia develops, the bone marrow will have more cells that cannot make proper blood cells, functionless blood cells will accumulate in the bone marrow, and the body will lose the functions of blood. Leukemia can start from either lymphocytes (L), which affect only the white blood cells, or myeloid cells (M), which affect white blood cells, red blood cells, and platelets. In terms of growth, leukemia is split into acute leukemia (A), which is when large amounts of useless blood cells rapidly accumulate in the bone marrow, and chronic leukemia (C), which is when the malfunctioning blood cells are not completely useless, and they don’t accumulate so fast in the bone marrow. Acute leukemia is where the cancer progresses faster, and symptoms can be felt sooner and stronger. Putting these codes together, CML stands for chronic myeloid leukemia, CLL stands for chronic lymphocytic leukemia, AML stands for acute myeloid leukemia, and ALL stands for acute lymphocytic leukemia. ALL is the most common type of cancer for children.


Please refer to this link for symptoms of leukemia and common risk factors. This link gives a comparison of symptoms of acute and chronic leukemia.


Image is courtesy of ncbi.nlm.nih.gov.


This is a bone. On the top is the red bone marrow containing stem cells that make different blood cells. The yellow marrow has stem cells that produce cartilage (the white connective tissue found where bones connect), fats, and bones.


Lymphoma


Image is courtesy of Cleveland Clinic.


Lymphoma is when white blood cells become cancerous and form tumours in the lymphatic system, which is the system that maintains fluid levels in the body, absorbs fat, and gets rid of waste. Here is the lymphatic system. The green pathway is the lymphatic vessels, and the small green dots are the lymph nodes. There are many white blood cells stored in lymph nodes, making the lymphatic system also a part of the immune system. When tumors form in lymph nodes or other parts of the lymphatic system, it will lose a part of its functions, resulting in the following symptoms according to the Mayo Clinic: Painless swelling of lymph nodes in your neck, armpits or groin, persistent fatigue, fever, night sweats, shortness of breath, unexplained weight loss, and itchy skin.


Picture of a swollen lymph node on the neck (pbmchealth.org).


Lymphoma is categorized into Hodgkin’s Lymphoma and Non-Hodgkin’s Lymphoma.


Hodgkin’s Lymphoma develops from B cells. This is a fairly rare type of cancer, and it has a high survival rate due to an advance in technology. In Hodgkin’s Lymphoma, there is a type of abnormal, cancerous lymphocyte that is called Reed-Sternberg cells, they are large and often of more than one nucleus, and they gather in lymph nodes. They can also spread to neighbouring lymph nodes through lymphatic vessels or to organs that are not a part of the lymphatic system. There is no definite cause to Hodgkin’s Lymphoma, but there is a theory that being infected by the Epstein-Barr virus may lead to a higher risk of Hodgkin’s Lymphoma since this virus infects B cells and makes them grow larger and live longer.


Image is courtesy of National Cancer Institute.


Non-Hodgkin’s Lymphoma starts from both B and T cells, another type of white blood cell. This is an umbrella term that covers some 60 types of Lymphoma with similar characteristics. All of them are cancers that affect the lymph system, and they can start anywhere in the system, the nodes or the organs. Non-Hodgkin’s Lymphoma can be classified based on how the cancer looks under the microscope, where the cancer started from, genetic features of the cancerous cells, whether there are certain proteins present on the surface of these cells, and the symptoms that they cause.


To know more about B cells and T cells, visit this link and this link.

Difference between Lymphoma and Leukemia from the Cleveland Clinic.


Myeloma


Myeloma, or multiple myeloma since it is often found in many parts of the body, is a cancer related to another type of white blood cell called plasma cells. While they are healthy, they make antibodies that can recognize viruses and then fight them off to protect the body. When they become cancerous, they stop producing useful antibodies, and they gather in the bone marrow, leaving no space for healthy cells to be produced. Sometimes, myeloma develops slowly and doesn’t show many symptoms, in which cases a treatment isn’t needed right away. When myeloma develops to show symptoms, these symptoms include (according to the Mayo Clinic): Bone pain, especially in your spine or chest, nausea, constipation, loss of appetite, mental fogginess or confusion, fatigue, frequent infections, weight loss, weakness or numbness in your legs, excessive thirst.


How to differentiate between blood cells (National Cancer Institute).


Conclusion


Here’s an anecdote to end it off. As I was procrastinating before writing this article, I saw an advertisement at the beginning of the video I was watching that asks viewers to donate to children with Leukemia and Lymphoma. The ad shows footage of the children in pain from the disease and treatment. They were crying, and their family members were crying too, pleading for us to save them. This is all due to the high expenses of treatments of leukemia, including regular chemotherapy as well as stem cell transplant in the bone marrow.


I’m glad that in some cases like Hodgkin’s Lymphoma, a cure was found; however, there are so many races that we still have to run to find a cure for other diseases. For the aggressive types of these cancers in children, they are curable, but they can also be fatal if they are not treated. Below are some articles related to leukemia in children. I hope this will introduce more people to this issue and what advances have been made.


Additional resources


Leukemia in children

Diagnosis and Treatment for AML in children

New drug discovery for treating AML

CART therapy

Injection for CLL



Article Author: Ivy Sun

Article Editors: Sherilyn Wen, Victoria Huang