What is anaplasia?

Anaplasia: Lack of differentiation is called anaplasia. Anaplasia is the hallmark of malignant transformation.

Anaplasia is marked by a number of morphological changes:

1. Pleomorphism: Variation in size and shape.
2. Abnormal nuclear morphology: The nuclei contain abundance of DNA and are extremely dark staining.
3. Mitoses: Malignant tumors usually poses mitoses
4. Loss of polarity: In addition to the cytological abnormalities, the orientation of anaplastic cells is markedly disturbed.
5. Other changes: Formation of giant cells.  

What is differentiation?

Differentiation:

Differentiation refer to the extent to which neoplastic cells resemble comparable to normal cells, both morphologically and functionally.

Write the role of gene in malignant transformation.

Role of gene in malignant transformation:

1. Nonlethal genetic damage lies at the heart of carcinogenesis. Some of the genetic damage may be acquired by the action of environmental agents such as chemicals or virus or may be inherited.
2. A tumor is formed in the clonal expansion of a single precursor cell that has incurred the genetic damage.
3. Four classes of normal regulatory genes - i) The growth promoting protooncogenes, ii) The growth inhibiting tumor suppressor genes, iii) Genes that regulate programmed cell death, iv) And genes involved in DNA repair are principal targets of genetic damage.
4. DNA repair genes affect cell proliferation or survival indirectly by influencing the ability of the organism to repair non-lethal damage in other genes, including proto-oncogenes, tumor suppressor genes and genes that regulate apoptosis
5. Carcinogenesis is a multistep process at both the phenotypic and the genetic levels.

Common Childhood malignancy.

Common childhood malignancy are as follows:

• Neuroblastoma
• Wilms tumor
• Retinoblastoma
• Acute Leukemia
• Rhabdomyosarcoma

How do cancer cells evade immune system?

Cancer cells can evade immune system by following mechanisms?

1. Failure to produce tumor antigen.
2. Mutations in MHC genes or genes needed for antigen processing.
3. Production of immune-suppressive proteins.

What is immunosurveillance?

Cancer immunosurveillance is a theory where proposed that lymphocytes acts as sentinels in recognizing and eliminating continuously arising nascent transformed cells. Cancer immunosurveillance appears to be an important host protection process that inhibits carcinogenesis and maintains regular cellular homeostasis. It has also been suggested that immunosurveillance primarily functions as a component of a more general process of cancer immunoediting.