Neoplasia

Question 1

What are two basic components of tumour

Answer 1

1. the parenchyma, made up of transformed or
   neoplastic cells, and
   (2) the supporting, host-derived, nonneoplastic stroma, made up of connective tissue, blood
   vessels, and host-derived inflammatory cells

Question 2

benign tumor arising in fibrous tissue is a

Answer 2

Fibroma

Question 3

What is the term for a malignant tumor of mesenchymal origin?

Answer 3

Sarcoma

Question 4

What are carcinomas?

Answer 4

Malignant epithelial tumors.

Question 5

What is an adenocarcinoma?

Answer 5

carcinoma with glandular patterns.

Question 6

What is a teratoma?

Answer 6

mixed tumor containing cells or tissues from more than one germ cell layer.

Question 7

What is a hamartoma?

Answer 7

disorganized mass of tissue native to the site, often considered developmental rather than neoplastic.

Question 8

What is a choristoma?

Answer 8

A congenital anomaly with a mass of normal tissue in an abnormal location.

Question 9

What is the difference in differentiation between benign and malignant tumors?

Answer 9

Benign tumors show complete differentiation, resembling their tissue of origin, while malignant tumors may show differentiation or anaplasia, characterized by loss of specialized features.

Question 10

How is anaplasia reflected in malignant tumors?

Answer 10

It involves large, variably shaped nuclei, disorganized cell growth (dysplasia), secretion of fetal proteins, mucin production in adenocarcinomas, and ectopic hormone secretion by non-endocrine tumors.

Question 11

List examples of ectopic hormones secreted by tumors

Answer 11

Lung carcinoma cells may secrete ACTH, parathyroid-like hormone, insulin, and glucagon

Question 12

: What is dysplasia, and how does it differ from anaplasia?

Answer 12

Dysplasia is disorganized cell growth, often seen in preneoplastic conditions, but it is potentially reversible. Anaplasia is irreversible and indicates malignant transformation.

Question 13

How does the rate of growth differ between benign and malignant tumors?

Answer 13

Benign tumors: Grow slowly and steadily.
Malignant tumors: Grow rapidly, with rates influenced by blood supply, hormonal factors, and differentiation. Poorly differentiated tumors grow faster.

Question 14

What factors influence tumor growth rate

Answer 14

Hormonal stimulation: Some tumors, like uterine leiomyomas, grow faster with hormonal changes.
Position: Tumors in restricted spaces (e.g., pituitary tumors in the sella turcica) have limited growth.

Question 15

Describe the local invasion characteristics of benign and malignant tumors.

Answer 15

Benign tumors: Are localized and encapsulated; they do not invade surrounding tissues.
Malignant tumors: Invade and infiltrate surrounding tissues by breaking through the basement membrane and extracellular matrix.

Question 16

What are the key steps involved in tumor invasion?

Answer 16

Detachment: Tumor cells lose adhesion due to E-cadherin inactivation.
Degradation: Proteolytic enzymes like matrix metalloproteinases (MMPs) degrade ECM components.
Attachment: Tumor cells bind ECM proteins such as collagen and laminin.
Migration: Tumor cells move through degraded ECM using cytokines and growth factors.

Question 17

Q: What is metastasis, and how is it achieved?

Answer 17

Metastasis is the spread of tumor cells to distant sites. It involves:

Invasion of the basement membrane.
Entry into blood or lymphatic vessels.
Formation of tumor emboli by aggregating with platelets and leucocytes.
Exit at a distant site (extravasation) and colonization.

Question 18

What determines organ-specific metastasis?

Answer 18

Tumour cells express certain chemokind receptors (e.g., CXCR4, CCR7) that bind ligands expressed by certain organs, directing metastasis to those sites.

Question 19

How do malignant tumors achieve angiogenesis

Answer 19

Malignant tumors secrete vascular endothelial growth factor (VEGF) and other factors that stimulate blood vessel formation to support rapid growth and metastasis.

Question 20

What are the hallmarks of malignancy

Answer 20

Invasion and infiltration of surrounding tissues.
Ability to metastasize.
Loss of differentiation (anaplasia).
High mitotic activity.
Resistance to apoptosis.

Question 21

Explain how tumors interact with the extracellular matrix (ECM) during invasion.

Answer 21

Tumors degrade the ECM using enzymes (e.g., MMPs), attach to ECM proteins, and modify ECM components to promote migration and resistance to apoptosis.

Question 22

What is the clinical relevance of tumor grading and staging?

Answer 22

Staging (TNM): Describes tumor size (T), nodal involvement (N), and metastasis (M), critical for prognosis and treatment planning

Question 23

Define preneoplastic conditions and explain their significance.

Answer 23

Preneoplastic conditions are acquired states that increase the likelihood of malignancy. Chronic inflammation associated with these conditions exposes cells to inflammatory products, leading to somatic mutations. Removal of the inflammatory cause can reverse tissue damage.

Question 24

Define preneoplastic conditions and explain their significance.

Answer 24

Preneoplastic conditions are acquired states that increase the likelihood of malignancy. Chronic inflammation associated with these conditions exposes cells to inflammatory products, leading to somatic mutations. Removal of the inflammatory cause can reverse tissue damage.

Question 25

Provide examples of preneoplastic conditions and their associated cancer risks.

Answer 25

Squamous metaplasia and dysplasia of bronchial mucosa in smokers: Risk of lung cancer.
Endometrial hyperplasia or dysplasia from excessive estrogen: Risk of endometrial carcinoma.
Leukoplakia of oral cavity, vulva, or penis: Risk of squamous cell carcinoma.
Villous adenoma of the colon: Risk of colorectal carcinoma.

Question 26

What are proto-oncogenes, and how do they contribute to cancer?

Answer 26

A: Proto-oncogenes are normal genes that promote cell growth and division. Mutations or activation of proto-oncogenes, such as RAS or EGFR, can convert them into oncogenes, leading to uncontrolled cell proliferation.

Question 27

What role does the TP53 gene play in cancer suppression?

Answer 27

The TP53 gene produces the p53 protein, which regulates the cell cycle, DNA repair, and apoptosis. Mutations in TP53 lead to loss of this tumor suppressor function, allowing damaged cells to proliferate unchecked.

Question 28

What role does the TP53 gene play in cancer suppression?

Answer 28

The TP53 gene produces the p53 protein, which regulates the cell cycle, DNA repair, and apoptosis. Mutations in TP53 lead to loss of this tumor suppressor function, allowing damaged cells to proliferate unchecked.

Question 29

What is the significance of the RB gene in cancer?

Answer 29

The RB gene regulates the G1-S phase transition by binding E2F transcription factors. Mutations in both copies of RB disable this control, leading to unregulated DNA replication and tumorigenesis.