Multiple myeloma (MM) is a type of B cell-related cancer originating from malignant plasma cells in the bone marrow. These cancerous plasma cells uncontrollably produce abnormal, immature immunoglobulins known as M-proteins. The primary cause of MM is believed to involve genetic abnormalities in the bone marrow microenvironment, such as mutations in oncogenes like MYC and IRF4, which drive malignant plasma cell proliferation. However, many details of this process remain unclear.

The exact causes of MM are not well understood, but genetic factors, race, and exposure to toxic chemicals in the environment or workplace are associated with higher risk. For instance, in the United States, MM is more prevalent among African Americans and older individuals.

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm (MPN) characterized by clonal proliferation of myeloid cells with varying degrees of maturity and hematopoietic efficiency. Clinically, PV is distinct from other MPNs by an increase in red cell mass (RCM) or elevated red blood cell counts, which raises blood viscosity and heightens the risk of thrombosis.

PV has an estimated incidence rate of 1.9 per 100,000 people annually and is generally considered a relatively indolent disease with a long survival period. Patients typically require lifelong management. Over time, typically within 20 to 30 years, PV may progress to myelofibrosis or leukemia. The risk of thrombosis, bleeding, and persistent symptoms significantly impacts patients' quality of life, making effective management crucial.

Essential thrombocythemia (ET) is a BCR-ABL-negative myeloproliferative neoplasm (MPN), characterized by clonal proliferation of myeloid cells with variations in maturity and hematopoietic efficiency. ET is distinguished by excessive platelet production and clonal platelet expansion, which predisposes patients to thrombosis and bleeding. Although at least half of ET patients are asymptomatic at diagnosis, most will experience vasomotor symptoms, thrombotic events, or bleeding episodes at some point during the disease course.

ET accounts for about one-third of BCR-ABL-negative MPN cases in developed countries. Epidemiological studies estimate an annual incidence of 1-2.5 cases per 100,000 people. Women are affected more frequently than men, with a female-to-male ratio of approximately 2:1. The incidence increases with age, with a median age of diagnosis around 60, although up to 20% of cases occur in individuals under 40. ET is generally considered an indolent condition with a near-normal life expectancy, but it requires lifelong management.

Myelofibrosis (MF) is a myeloproliferative neoplasm characterized by clonal proliferation of bone marrow cells with varying degrees of maturity and hematopoietic efficiency. The disease leads to significant fibrosis in the bone marrow, impairing its ability to produce blood cells effectively.

The incidence of MF is estimated at approximately 4 per 100,000 people, with generally prolonged survival. While no large-scale epidemiological data exists specifically for MF in China, South Korean data suggests a similar incidence of about 4 per 100,000 annually, including primary MF, post-polycythemia vera myelofibrosis (post-PV-MF), and post-essential thrombocythemia myelofibrosis (post-ET-MF), with rates appearing to rise. MF is primarily a disease of older adults, with a median age of onset around 67. Approximately 5% and 17% of cases are diagnosed before ages 40 and 50, respectively, with pediatric cases being rare.

According to Frost & Sullivan estimates, China had approximately 61,000 MF patients in 2021. Despite the long survival period associated with MF, patients face high disease burden. Data from Phase III trials of ruxolitinib, a common treatment, indicate a median overall survival (OS) of 5.3 years in MF patients. However, in patients with intermediate- to high-risk MF, survival decreases to approximately 2-3 years.

Rheumatoid Arthritis (RA) is an autoimmune disease primarily characterized by erosive arthritis, with hallmark pathological features including synovitis and pannus formation. Over time, these changes lead to the destruction of joint cartilage and bone, ultimately resulting in joint deformity and loss of function.

The global prevalence of RA is around 0.5-1%, with an estimated prevalence in mainland China of 0.42%, affecting approximately 5 million people. The female-to-male ratio is approximately 4:1. Disability rates among RA patients in China increase with disease duration: 18.6% for those with 1-5 years, 43.5% for 5-10 years, 48.1% for 10-15 years, and 61.3% for over 15 years. RA significantly impacts physical function, quality of life, and social participation for patients, creating substantial economic burdens for both families and society.

Inflammatory bowel disease (IBD) is a chronic inflammatory bowel condition of unknown origin that causes inflammation in the digestive tract. It primarily affects the large intestine (ulcerative colitis) and the whole gastrointestinal tract (Crohn's disease).

IBD has become a significant global health issue, particularly in Western countries. While its prevalence has stabilized in some regions, it continues to rise in others, especially among children. Emerging economies, such as those in Asia, South America, and Africa, are experiencing a rapid increase in IBD cases. China, in particular, is witnessing a significant surge in IBD prevalence, with an estimated 1.5 million patients projected by 2025.