WHAT IS CANCER?

o Normal cells divide rapidly to supply the new growth necessary to replace injured
cells, then return to a normal rate of division. But in the case of Cancer, the
cancer cells divide haphazardly or abnormally. This abnormal cell growth
leads to formation of a non structured mass called neoplasm or tumor (neoplasm
or tumor is a group of cells that have undergone unregulated growth, and will
often form a mass or lump) leading to Cancer.
o Definition; Cancers as a group of diseases that are characterized by the
uncontrolled growth and spread of abnormal cells OR Cancers are a large family
of diseases that involve abnormal cell growth with the potential to invade
or spread to other parts of the body.
 LEUKEMIA (BLOOD CANCER)

Definitions; The term leukemia comes from the Greek words for (leukos) “white” and (haima) “blood”.

Leukemia is cancer of the blood or bone marrow (which produces blood cells) and is caused by the
rapid production of abnormal white blood cells (leukocytes) OR Leukemia represents a group of
diseases characterized by dysregulated proliferation and incomplete maturation of the precursors to
white cells and lymphocytes OR Leukemia is a malignant disease of hematopoietic tissue
characterized by the accumulation abnormal white cells (neoplastic or leukemic) in the bone
marrow leading to bone marrow failure, a raised circulating white cell count (leukocytosis) and
infiltrate organs (e.g liver, spleen, lymph nodes, brain) OR Leukemia, a type of cancer found in
blood and bone marrow, is caused by the rapid production of abnormal white blood cells. The high
number of abnormal white blood cells are not able to fight infection, and they impair the ability of the
bone marrow to produce red blood cells and platelets. Leukemia does not generally form a mass.
 Large variable shaped nuclei Variation in cell size and shape Loss of normal specialized features Large number of dividing cells
Relatively, small cytoplasmic volume Disorganized arrangement of cells Elevated expression of certain cell markers Poorly defined tumor boundaries

Cancer cells

Example of Morphological
changes in Cancer cells

Normal Cells

Small, Uniformly shaped nuclei Conformity in cell size and shape May possess differentiated cell structures Lower levels of dividing cells

Relatively large cytoplasmic volume Cells arranged into discrete tissues Normal presentation of cell surface markers Cell tissues clearly demarcated
 Platelet Platelet
White Cell Red Cell Red Cell Blasts
White Cell

Normal human blood Blood with leukemia

Signs of Leukemia (BLOOD CANCER)

The symptoms will vary according to the types of leukemia.

• Tired, Frequent infections, Easy bruising or bleeding, Bone tenderness, Headache,
Enlarged lymph nodes, Low red blood count, Pale skin, Poor appetite.

• Symptoms Of Blood Cancer

• Due to decrease in Level of RBC- Fatigue- since brain does not get appropriate amount of
oxygen, Weakness, Shortness of breath, Paler look- due to decreased red blood cells which impart
a red color to the blood.

• 2. Due to decreased Platelets:- No clotting leading to prolonged bleeding.

• 3. Due to decreased WBC. Frequent or increased susceptibility to infections, Weight loss, Pain in
bones
 Etiology of Leukemia
Different leukemias have different causes.
Artificial ionizing radiation, Exposure to intense radiation.
Viruses - HTLV-1 (human T-lymphotropic virus) and HIV (human immunodeficiency virus)
Petrochemicals like Benzene and some Hair dyes
Genetic predisposition – Family History
Down syndrome.
Electromagnetic energy
 PATHOPHYSIOLOGY OF LEUKEMIA
• Leukemia is malignant cancer of the cells derived from either the myeloid or lymphoid line of the
hematopoietic stem cells in the bone marrow. When hematopoietic stem cells divide into lymphoid
stem cells, they then convert into lymphoblasts. These lymphoblasts usually gets converted into
mature B-lymphocytes or T-lymphocytes.

• But in leukemia, these lymphoblasts are arrested in this immature cell phase and are never converted
into mature cells which just results in too many immature incompetent cells just taking up space for
nothing. Proliferating abnormal and immature cells (blast) spill out into the blood and infiltrate the
spleen, lymph nodes, and other tissue. It further leads to problems like anemia, thrombocytopenia and
bone pain etc.

• Leukemia starts when the DNA of a single cell in bone marrow changes (mutates) and cannot develop
and function normally. Because of the mutation, or coding error, leukemia cells keep multiplying.

• All cells arising from the original mutated cell also have the mutated DNA.
Classification of leukemia
Two major types (4 subtypes) of leukemias

1. Acute leukemias (white blood cells tend to develop more rapidly and very
immature)

a. Acute lymphoblastic leukemia (ALL)

b. Acute myelogenous leukemia (AML) (also myeloid, granulocytic or
nonlymphocytic)

2. Chronic leukemias (white blood cells tend to develop more slowly)

b. Chronic lymphocytic leukemia (CLL) (lymphoid cells are affected)

c. Chronic myeloid leukemia (CML) (myeloid cells are affected)

• Acute myelogenous leukemia (AML) also known as acute myeloblastic leukemia, acute
granulocytic leukemia and acute nonlymphocytic leukemia.
• AML is called myelogenous leukemia because it affects a group of white blood cells called
the myeloid cells, which normally develop into the various types of mature blood cells, such
as RBC, WBC and platelets.

• AML is a rare cancer of the blood and bone marrow and develops as the consequence of a
series of genetic changes in a hematopoietic precursor cell. These changes alter normal
hematopoietic growth and differentiation, resulting in an accumulation of large numbers of
abnormal, immature myeloid cells in the bone marrow and peripheral blood. These cells are
capable of dividing and proliferating, but cannot differentiate into mature hematopoietic cells.
Acute lymphocytic leukemia (ALL) also known as acute lymphoblastic leukemia is a
malignancy of B or T lymphoblasts characterized by uncontrolled proliferation of abnormal,
immature lymphocytes and their progenitors which ultimately leads to the replacement of
bone marrow elements and other lymphoid organs resulting in a characteristic disease
pattern.
In ALL, the disease progresses rapidly and creates immature white blood cells called
lymphocytes, rather than mature ones. Acute lymphocytic leukemia is the most common
type of cancer in children and adults, though the chance of a cure is greatly reduced.
Signs and symptoms may appear abruptly
Fever, bleeding, Weakness, fatigue.
Chronic Myeloid Leukemia (CML)
• Chronic myelogenous leukemia (chronic granulocytic leukemia, chronic myelocytic leukemia, chronic
granulocytic leukemia) is a slowly progressing blood and bone marrow disease that is characterized by
increased production of granulocytes in the bone marrow.

• The course of CML is divided into three phases: the chronic phase, the acceleration phase, and the blast
phase (Chronic, stable phase followed by acute, aggressive (blastic) phase).
• In CML, a genetic change takes place in an early (immature) version of myeloid cells -- the cells that
make red blood cells, platelets, and most types of white blood cells (except lymphocytes). This change
forms an abnormal gene called BCR-ABL, which turns the cell into a CML cell. The leukemia cells grow
and divide, building up in the bone marrow and spilling over into the blood. In CML, too many blood stem
cells become a type of white blood cell called granulocytes. These granulocytes are abnormal and do not
become healthy white blood cells. CML is a fairly slow growing leukemia, but it can change into a fast-
growing acute leukemia that ultimately infiltrate the liver and spleen.
Chronic Lymphocytic Leukemia (CLL)
• Lymphocytic leukemias involve immature lymphocytes and their progenitors. They arise in the bone marrows but

infiltrate the spleen, lymph nodes, CNS and other tissues. Multiple genetic mutations occur in the DNA of blood-

producing cells. CLL happens when there are changes in the genetic material (DNA) in bone marrow cells.

These mutations cause the blood cells to produce abnormal lymphocytes, and are not effective at fighting

infection.

• When the abnormal cells crowd out the healthy cells, it can lead to infection, anemia, and bleeding tendency.

The abnormal cells can also spread outside the blood to other parts of the body. CLL is one of the most common

types of leukemia in adults and rare in children.

• Symptoms include Swollen lymph nodes, Weakness or feeling tired, Pain or a feeling of fullness below the ribs,

Fever and infection, Easy bruising or bleeding, Weight loss, Drenching night sweats.

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 Comparison of acute and chronic leukemia

Acute Chronic
Age All ages Adults
Clinical onset Sudden Insidious
Leukemic cells Immature WBC Mature WBC
Anemia Mild to severe Mild
Thrombocytopenia Mild to severe Mild
WBC Variable Increased
Organomegaly Mild prominent
Tests For Diagnosis
• Finger prick
• Imaging Tests – CT Scans, MRI can spot signs of leukemia
• Blood sample; Peripheral blood evaluation (CBC and blood smear) to see
unusual or Immature cells.
• Bone marrow sample; Marrow taken from a pelvic bone that shows what kind
of leukemia a patient have and how severe it is.
• Morphologic, histochemical, immunologic, and cytogenic methods
• Spinal Tap/Lumbar Puncture

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 Assignments # 3 and 4

1. Hypertension; environmental factors, identification, management, treatment.

2. Leukemia; pathogenesis, transmission and types.

Each assignment must be separately submitted with more than 1000 words each.

Student name, Teacher name, CECOS logo, Times new roman 12 fonts with justification.

Please submit by February, 27th.