characteristics of a tumour

Question 1

what is a tumour?

Answer 1

it is any swelling or mass

Question 2

what is a neoplasia?

Answer 2

a new uncontrolled growth of cells that is not under physiological control - malignant or benign

Question 3

what is a cancer?

Answer 3

it is a generic term for a large group of diseases that are characterised by the abnormal growth of cells beyond their usual boundaries that can then invade adjoining parts of the body and spread to other organs

Question 4

what is the formation of differentiated tissue from undifferentiated ecto, endo and mesoderm?

Answer 4

embryological histogenesis

Question 5

what is the most internal layer and what does it form?

Answer 5

endoderm and forms digestive cells, lung cells and thyroid cells

Question 6

what is the middle layer and what does it form?

Answer 6

mesoderm and it forms skeletal, cardiac and smooth muscle cells, tubule cells of kidney and RBCs

Question 7

what is the outer layer and what does it form?

Answer 7

it is the ectoderm and it forms the neurons of the brain pigmentation cells and the skin cells of the epidermis

Question 8

what is tumour histogenesis?

Answer 8

tumours are names according to the tissue of origin - sarcoma is mooth muscle cells, carcinoma is endoderm and melanoma is ectoderm

Question 9

what is differentiation?

Answer 9

it is the extent to which a neoplasm resembles the tissue of origin - well (resembles a lot), moderate and poor

Question 10

what is anaplasia?

Answer 10

it is a neoplasm that is poorly differentiated and highly pleomorphic

Question 11

what are the hallmarks of cancer?

Answer 11

environmental factors and genetic factors make mutations accumulate to make the hallmarks of cancer - these are inducing angiogenesis, activating invasion and metastasis, avoiding immune destruction. enabling replicative immortality, evading growth supressors, sustaining proliferative signalling, resisting cell death and deregulating cellular energetics - make a malignant cell

Question 12

what is the lifetime risk of squamous cell and basal cell carcinoma and what is their death rate?

Answer 12

around 10% lifetime for squamous and 30% for basal - together are less than 1% of cancer deaths

Question 13

what are the most common and most fatal cancers?

Answer 13

breast, lung and then bowel for commonness in females but lung, breast bowel or mortality
for males prostate lung then bowel for commonness and for mortality is lung prostate bowel
this excludes non melanoma skin cancers

Question 14

what are the most common types of cancer in LEDCs?

Answer 14

oral (alcohol etc), liver (hep) or Kaposki sarcoma (HIV/Lip) or cervical or breast in males

Question 15

what has the lowest survival for males and females and the highest?

Answer 15

highest in females is melanoma of skin and males is testicular
lowest for females and males is pancreatic

Question 16

what is the HPV virus course to cause cancer?

Answer 16

normal - very mild - moderate - sever dysplasia - in situ carcinoma - invasive carcinoma

Question 17

what are the differences between malignant and benign?

Answer 17

invasion - not present in benign
metastasis - not in benign, in invasive is lymphatic, direct seeding or haematogenous
prognosis - fatal often in malignant, unless in CNS not fatal in benign
differentiation - well in benign and anaplastic in malignant eventually
rate of growth - slow in benign fast in malignant

Question 18

what are the complications of primary tumours?

Answer 18

invasion into and replacement of normal tissue and pressure on normal tissue - failure to function of organ
invasion into blood vessels and pressure leading to bleeding and ischaemia
pressure and invasion into nerves leading to pain and loss of function
growing into lumen leading to obstruction
ulceration

Question 19

what is distant metastasis?

Answer 19

when the tumour spreads to a different part of the body forming secondary tumours

Question 20

what are the complications of secondary tumours?

Answer 20

invasion into vessels, lumens and tissues and nerves

Question 21

what are paraneoplastic syndrome?

Answer 21

they are signs and symptoms that are not related to the effects of the primary or secondary tumours and develop as a result of proteins or hormones secreted by the tumour cells that result in cachexia or cushings, or immune cross reactivity between tumour cells and normal resulting in lambert eaton myasthenic syndrome

Question 22

what is parenchyma?

Answer 22

they are the cells that perform the actual function of an organ - cells that do gas exchange in the lungs (pneumocytes) or contact in heart for contraction (mycoytes)

Question 23

what supports the parenchyma?

Answer 23

stroma

organ = stroma + parenchyma

Question 24

what are tumour stroma?

Answer 24

they are composed of the same cell types as normal stroma but the stromal cells have different functions

Question 25

what are stromal cells composed of?

Answer 25

blood vessels, fibroblasts and the collagen they make and immune cells

Question 26

what is the role of normal stromal cells?

Answer 26

they support the parenchyma
play a role in inflammation
control of accumulation of cells in inflammation sites

Question 27

what are tumour stromal cells for?

Answer 27

tumour metastasis initiation and regulation and allow the cell to acquire the hallmarks of cancer and become malignant