Myeloma, often referred to as multiple myeloma, is a type of blood cancer that originates in the plasma cells within the bone marrow. Bone marrow, the spongy tissue inside larger bones, is responsible for producing various types of blood cells. Plasma cells are specialized white blood cells crucial to the immune system, tasked with creating antibodies to combat infections. In myeloma, the bone marrow is overtaken by an excessive production of abnormal, cancerous plasma cells.
Delving Deeper into Plasma Cells
Plasma cells are integral components of the body’s immune defense system. Healthy plasma cells produce proteins known as antibodies, or immunoglobulins. These antibodies are essential for recognizing and neutralizing pathogens like bacteria and viruses, thus protecting the body from infections. When the body encounters an infection, plasma cells respond by producing specific antibodies tailored to fight that particular invader. There are five primary types of antibodies: IgA, IgG, IgM, IgD, and IgE, each playing a unique role in immune responses.
How Myeloma Develops: A Cellular Level Perspective
Myeloma arises from genetic mutations within plasma cells. These mutations, occurring during the process of bone marrow generating new plasma cells, disrupt the normal cellular instructions encoded in DNA. This altered DNA leads to the development of abnormal plasma cells, known as myeloma cells. These cancerous cells then proliferate uncontrollably, creating a surplus of abnormal plasma cells within the bone marrow.
A key characteristic of myeloma cells is their production of abnormal antibodies called paraproteins, also known as monoclonal proteins or M-proteins. These paraproteins are dysfunctional and unable to effectively fight infections. Doctors may refer to them by various names, including abnormal proteins or monoclonal spikes. Paraproteins, and specifically their light chain component known as Bence Jones protein, can be detected in blood and urine tests. These tests are crucial for diagnosing myeloma and monitoring its progression. The body eliminates these light chains through urine, making urine and blood tests valuable diagnostic tools.
The Impact of Myeloma on the Body
Unlike many cancers, myeloma doesn’t typically form solid tumors. Instead, its effects stem from the accumulation of abnormal plasma cells in the bone marrow and the presence of paraproteins throughout the body. Myeloma affects areas with active bone marrow, including the spine, pelvis, rib cage, skull, shoulders, arms, and legs. The widespread nature of myeloma is why it’s often termed multiple myeloma, signifying its presence in multiple bone marrow sites.
To understand the far-reaching consequences of myeloma, it’s important to consider the normal function of blood cells.
Blood Cells and Myeloma’s Disruption
Normally, bone marrow diligently produces blood cells in a regulated manner, responding to the body’s needs. All blood cells originate from stem cells, which then mature into three main types:
- White blood cells (leukocytes): Essential for fighting infections.
- Red blood cells (erythrocytes): Responsible for oxygen transport throughout the body.
- Platelets (thrombocytes): Crucial for blood clotting.
Plasma cells are derived from a specific type of white blood cell called B lymphocytes. In myeloma, the uncontrolled proliferation of cancerous plasma cells overcrowds the bone marrow. This crowding effect diminishes the bone marrow’s capacity to produce normal white blood cells, red blood cells, and platelets.
Consequences of Myeloma on Blood Cell Function
The disruption of normal blood cell production due to myeloma leads to various health issues:
- White blood cell deficiency (Leukopenia): Reduces the body’s ability to fight infections, leading to increased susceptibility and prolonged infections.
- Red blood cell deficiency (Anemia): Causes fatigue and breathlessness due to reduced oxygen-carrying capacity.
- Platelet deficiency (Thrombocytopenia): Increases the risk of bleeding, manifesting as nosebleeds, heavy menstrual periods, or petechiae (small red spots on the skin).
Furthermore, the paraproteins produced by myeloma cells can thicken the blood, potentially leading to symptoms like dizziness and headaches. Myeloma cells can also infiltrate and damage bones, causing pain, fractures, and the release of calcium into the bloodstream (hypercalcemia). High calcium levels can result in symptoms such as thirst, constipation, and confusion. Kidney damage is another potential complication of myeloma.
Types of Myeloma and Related Conditions
Myeloma is categorized into different types based on the specific type of paraprotein produced by the myeloma cells. IgG myeloma is the most prevalent type, followed by IgA myeloma and light chain myeloma. IgM, IgD, and IgE myelomas are less common.
Several related conditions involve plasma cell disorders, including:
- Monoclonal gammopathy of undetermined significance (MGUS): A precursor condition where abnormal protein is present but without meeting full myeloma criteria.
- Plasmacytoma: A solitary tumor of plasma cells, often in bone or soft tissue.
- Amyloidosis: A condition where abnormal proteins deposit in organs and tissues, sometimes associated with plasma cell disorders.
Myeloma Prevalence and Who is Affected
Myeloma is a relatively rare cancer, but it is becoming more recognized. In the UK, approximately 6,200 individuals are diagnosed with myeloma each year. Myeloma is more frequently diagnosed in men than women and is predominantly a disease of older adults. The majority of new cases occur in individuals aged 75 and older, and it is uncommon in people under 40.
Understanding myeloma, its origins in plasma cells, and its widespread effects is crucial for early detection and effective management of this blood cancer.
