Leukamia-Part 1

Question 1

What is the most common cancer in the 15-24 age group?

Answer 1

Cancers of the blood

Question 2

What is the literal meaning of leukaemia?

Answer 2

White blood

Question 3

Where does the problem exist in leukaemia?

Answer 3

In the bone marrow (not all patients have abnormal cells in the blood)

Question 4

What does leukaemia result from?

Answer 4

A series of mutations in a single lymphoid or myeloid stem cell

Question 5

Leukamia results from a series of mutations in a single lymphoid or myeloid stem cell. What are the consequences to the progeny of the mutated cell .

Answer 5

These mutations lead to progeny of that cell to show abnormalities in proliferation, differentiation or cell survival leading to steady expansion of the leukaemic clone

Question 6

Which cells can be affected in leukaemia?

Answer 6

Pluripotent haematopoietic stem cell Myeloid stem cell Lymphoid stem cell Pre B lymphocyte Pro T lymphocyte

Question 7

What are the equivalent terms for ‘benign’ and ‘malignant’ in terms of leukaemia?

Answer 7

Leukaemias that behave relatively benignly are CHRONIC Leukaemias that behave in a malignant manner are ACUTE– the disease is very aggressive

Question 8

What are the four main types of leukaemia?

Answer 8

Acute lymphoblastic leukaemia Acute myeloid leukaemia Chronic lymphocytic leukaemia Chronic myeloid leukaemia

Question 9

Explain the significance of the terms acute lymphoblastic leukaemia and chronic lymphocytic leukaemia.

Answer 9

In ALL the cells are immature – they are lymphoblasts IN CLL the cells are mature lymphocytes

Question 10

What are the important leukaemogenic mutations that have been recognised?

Answer 10

Mutation in a known proto-oncogene Creation of a novel gene e.g. chimeric or fusion gene Dysregulation of a gene when translocation brings it under the influence of a promoter or enhancer of another gene

Question 11

State some inherited or other constitutional abnormalities that can contribute to leukaemogenesis.

Answer 11

Down syndrome Chromosomal fragility syndromes Defects in DNA repair Inherited defects in tumour suppressor genes

Question 12

What are some identifiable causes of leukaemogenic mutations?

Answer 12

Irradiation Anti-cancer drug Cigarette smoking Chemicals e.g. benzene

Question 13

What type of cell is seen in abundance in acute myeloid leukaemia?

Answer 13

Immature myeloid cells – the cells continue to proliferate but they no longer mature so there is a build up of immature cells (myeloblasts) in the bone marrow, which spread to the blood

Question 14

Explain how acute leukaemia leads to bone marrow failure.

Answer 14

The leukaemic cells crowd out the normal cells in the bone marrow leading to a decrease in the production of other end cells e.g. neutrophils, monocytes, platelets

Question 15

What do the responsible mutations normally affect in AML?

Answer 15

Transcription factors – the transcription of multiple genes is affected Often the product of an oncogene prevents the normal function of theprotein encoded by its normal homologue This leads to changes in cell kinetics and cell functions

Question 16

What do the responsible mutations normally affect in CML?

Answer 16

A gene encoding a protein in the signalling pathway between a cell surface receptor and the nucleus The protein encoded may be a membrane receptor or a cytoplasmic protein

Question 17

Explain the whole need for different terminology from the usual ‘benign’ and ‘malignant’ when describing leukamia

Answer 17

They are different from normal cancer cells(different from solid tumours) because:

Leukaemic cells teplace normal bone marrow cells and circulate in the blood. Hematopoetic stem cells leave bone marrow to go into the blood then go to the tissues, All cells derivied from them can go into tissues.Lymphoid cells recirculate between tissues and blood.Myleoidc cells obviously just goes in that one direction.Therefore you cant use observed invasion and metastasis for their classificiation into benign and malignant, therefore need other terminologies

Question 18

How is leukaemia classified?

Answer 18

• leukaemia can be acute or chronic
• Depending on the cell of origin, it can also be lymphoid or myeloid
• Lymphoid can be B or T lineage
• Myeloid can be any combination of granulocytic, monocytic, erythroid or megakaryocytic

Question 19

WHICH IMAGE IS SHOWING CHRONIC MYLOID LEUKAMIA AND WHICH IS SHOWING ACUTE MYELOID LEUKAMIA

Answer 19

RIGHT IS SHOWIN acute, left is showing chronic