Intro to Heme Malig

Question 1

List the main manners in which hematologic malignancies may manifest, and explain how these may overlap.

Answer 1

A prime example of such overlap is chronic lymphocytic leukemia (CLL) / small lymphocytic lymphoma (SLL). CLL and SLL are the same biologic disease, the difference between the terms being whether the disease is primarily involving the blood and marrow (CLL), or primarily present as enlarged lymph nodes due to solid growth (SLL). In many cases, both manifestations might be prominent, and the term “CLL/SLL “ can be used.

Question 2

Contrast basic concepts of high versus low grade lymphomas, and of acute versus chronic leukemias.

Answer 2

High grade: rapidly enlarging mass.
Acute leukemia: very high WBC count w/ near replacement of all normal cells
Low grade: mildly enlarged neck LN that has been present for years, noticed incidentally on an imaging study.
Chronic leukemia: very subtle symptoms, noticed incidentally on CBC performed for some other reason

Question 3

Recall the biological reason that many lymphomas contain balanced translocations involving the immunoglobulin and T cell receptor genes.

Answer 3

It’s due to the natural susceptibility of the genome to translocations during normal periods of genomic instability, namely during the initial immunoglobulin / T-cell receptor rearrangement during the maturation of B cells / T cells, and during the class recombination and somatic hypermutation process during the activation of B cells.

Question 4

Relate the importance of specific recurrent translocations in certain hematologic malignancies in regard to the clinical care of patients.

Answer 4

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Question 5

List 3 viruses known to have oncogenic roles in some cases of lymphoma.

Answer 5

EBV: implicated in the development of some cases of Hodgkin lymphoma, some cases of Burkitt lymphoma, and some B-cell NHLs
Human T cell leukemia virus-1 (HTLV-1): implicated in the development of adult T cell leukemia/lymphoma
Kaposi sarcoma herpesvirus/Human herpesvirus 8 (KSD/HHV-8): implicated in primary effusion lymphoma

Question 6

Contrast the incedences of leukemia and lymphoma in adult populations versus childhood populations.

Answer 6

In the National Cancer Insititute’s list of frequency of U.S. cancers by site for all ages/races,
non-Hodgkin lymphoma is 7th most frequent, and the generic category “leukemia” is 10th most frequent. To put this in more tangible terms, non-Hodgkin lymphoma and leukemia occur at rares that are about four to five times lower than the rates of the most common cancers, such as prostate cancer and breast cancer.
Regarding childhood cancers (age <20), leukemia is the most common type, representing 37% of childhood cancers. Lymphoma is the 3rd most common type, representing 24% of childhood cancers. (Second place belongs to brain/CNS tumors).

Question 7

7. Recall the currently recommended classification system for hematologic malignancies, and list parameters this system may use to aid in the classification of these malignancies.

Answer 7

WHO standard:

• microscopic appearance of the malignant cells
• histologic growth pattern of the malignant cells in the marrow, lymph node, or other tissue
• presence or absence of specific cytogenetic findings or molecular findings
• relative amount of malignant cells present in the blood or marrow
• presence or absence of certain cell surface markers / cytoplasmic markers / nuclear markers

Question 8

8. List the basic functional categories for hematologic malignancies, as outlined in the notes, and contrast the basic expected findings in the blood and marrow for these categories.
   Acute leukemias & MDS are myeloid categories

Answer 8

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