For a long time, leukemia has been a terminal disease that people are afraid to talk about. It is true that once a patient comes in with fever, infection, bleeding, enlarged liver and spleen lymph nodes or abnormal blood count and is initially diagnosed with “acute leukemia” in the outpatient or emergency room, he is prioritized for hospitalization even if there are more patients registered in front of him, because if not treated in time, survival is usually only a few months. If left untreated, survival is usually only a few months. However, leukemia is vicious, but also has its “soft spot”, and this “soft spot”, is the target of treatment, is the door to the road to a cure. Yes, once humans have mastered the “soft spot”, the goal of leukemia treatment is not just to control the disease, but to cure it! So, where exactly is the “soft spot” of leukemia?
1, leukemia typing It is important to know that there are many subtypes of leukemia. Why subtypes? This is an important result of long-term research by generations of medical doctors and scientists, different subtypes, “soft spot” is also different. Usually, leukemia is divided into two categories: acute leukemia and chronic leukemia. With advances in immunology (I), cytogenetics (C) and molecular biology (M), clinical typing of leukemia has shifted from relying solely on morphology (M) to the more refined and accurate MICM typing, which combines morphology, immunology, cytogenetics and molecular biology for diagnostic typing, so that treatment is more precise and the development of new therapeutic drugs is more targeted.
2.How to perform MICM typing?
MICM typing starts with the most basic morphological examination. By examining routine blood, peripheral blood film classification, bone marrow smear and bone marrow biopsy, most patients can be clearly diagnosed whether they have leukemia, whether it is acute or chronic, and whether it is gonorrhea or myeloid. Before immunology, cytogenetics and molecular biology were used in the diagnosis of leukemia, hematologists relied on morphological examinations for leukemia classification.
However, because leukemia cells are abnormally differentiated cells, their morphology often varies, and what you see with your eyes as one type of cell is actually just an illusion, and may be another type of cell, which often leads to misdiagnosis and affects the effectiveness of treatment. With immunological tests, we can determine whether the leukemia cells are derived from T lymphocytes, B lymphocytes? Or granulocytes, monocytes? Or is it red lineage cells, megakaryocytes? Or even mixed cells, dual phenotype cells? Immunological examination is usually done by flow cytometry using bone marrow fluid or peripheral blood.
Cytogenetic and molecular biology tests give us a better chance to get closer to the “soft spot”. Cytogenetic testing is to find out if there are chromosomal abnormalities, while molecular biology is to find out if there are genetic mutations. For example, we now know that there are chromosome 9 and 22 translocations (also known as the Philadelphia chromosome) and BCR-ABL fusion genes in chronic myeloid leukemia, chromosome 15 and 17 translocations and PML-RARĪ± fusion genes in acute promyelocytic leukemia, chromosome 8 and 21 translocations and AML1-ETO fusion genes in an acute granulocytic leukemia, and so on. Don’t underestimate the importance of knowing these chromosomes and genes. It is precisely the mutations in these genes that lead to chromosomal abnormalities and ultimately to the development of various leukemias. It is also the discovery of these abnormalities that allows hematologists to make accurate diagnoses and prognostic judgments about subtypes of leukemia and allows scientists to develop targeted therapeutic drugs for these abnormalities. In other words, genetic and chromosomal abnormalities are the “soft underbelly” of leukemia. Cytogenetic and molecular biology tests require the extraction of the patient’s bone marrow fluid and peripheral blood through delicate laboratory instruments.
3.What targeted therapeutic drugs are available for leukemia?
Since targeted therapies only target leukemia cells and cause less damage to normal cells, they are very popular among patients and doctors, and have inspired scientists to continue to discover “targets” and develop new targeted drugs. Currently, for the Philadelphia chromosome and BCR-ABL fusion gene in chronic myeloid leukemia, we have first-, second-, and third-generation tyrosine kinase inhibitors Imatinib (Gleevec), Nilotinib, Dasatinib, and Bosutinib; for chromosome 15 and 17 translocations and PML-RARĪ± fusion gene in acute promyelocytic leukemia, we have all-trans retinoic acid and arsenic; for B-cell immune markers on chronic lymphocytic leukemia, we have rituximab …… As targeted drugs become more and more available and precise, the treatment of leukemia becomes more and more effective, the survival of patients becomes longer, and curing leukemia is no longer an unattainable dream.