characteristics of a tumour Flashcards
what is a tumour?
it is any swelling or mass
what is a neoplasia?
a new uncontrolled growth of cells that is not under physiological control - malignant or benign
what is a cancer?
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
what is the formation of differentiated tissue from undifferentiated ecto, endo and mesoderm?
embryological histogenesis
what is the most internal layer and what does it form?
endoderm and forms digestive cells, lung cells and thyroid cells
what is the middle layer and what does it form?
mesoderm and it forms skeletal, cardiac and smooth muscle cells, tubule cells of kidney and RBCs
what is the outer layer and what does it form?
it is the ectoderm and it forms the neurons of the brain pigmentation cells and the skin cells of the epidermis
what is tumour histogenesis?
tumours are names according to the tissue of origin - sarcoma is mooth muscle cells, carcinoma is endoderm and melanoma is ectoderm
what is differentiation?
it is the extent to which a neoplasm resembles the tissue of origin - well (resembles a lot), moderate and poor
what is anaplasia?
it is a neoplasm that is poorly differentiated and highly pleomorphic
what are the hallmarks of cancer?
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
what is the lifetime risk of squamous cell and basal cell carcinoma and what is their death rate?
around 10% lifetime for squamous and 30% for basal - together are less than 1% of cancer deaths
what are the most common and most fatal cancers?
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
what are the most common types of cancer in LEDCs?
oral (alcohol etc), liver (hep) or Kaposki sarcoma (HIV/Lip) or cervical or breast in males
what has the lowest survival for males and females and the highest?
highest in females is melanoma of skin and males is testicular
lowest for females and males is pancreatic
what is the HPV virus course to cause cancer?
normal - very mild - moderate - sever dysplasia - in situ carcinoma - invasive carcinoma
what are the differences between malignant and benign?
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
what are the complications of primary tumours?
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
what is distant metastasis?
when the tumour spreads to a different part of the body forming secondary tumours
what are the complications of secondary tumours?
invasion into vessels, lumens and tissues and nerves
what are paraneoplastic syndrome?
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
what is parenchyma?
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)
what supports the parenchyma?
stroma
organ = stroma + parenchyma
what are tumour stroma?
they are composed of the same cell types as normal stroma but the stromal cells have different functions
what are stromal cells composed of?
blood vessels, fibroblasts and the collagen they make and immune cells
what is the role of normal stromal cells?
they support the parenchyma
play a role in inflammation
control of accumulation of cells in inflammation sites
what are tumour stromal cells for?
tumour metastasis initiation and regulation and allow the cell to acquire the hallmarks of cancer and become malignant
