Cancers Flashcards
Describe non-polypopsis hereditary colorectal cancer
tumour site throughout colon rather than descending colon
Increase in extra colonic cancers in organs with high cell turnover
Define Non-polypopsis and polypopsis
non-polypopsis - few to no adenomas
polypopsis - multiple adenomas
Which organs have a high cell turnover
endometrium, ovary, stomach
Describe the 3 types of polyposis hereditary colorectal cancer
FAP- 100% risk of cancer, CHRPE
AFAP - later onset with fewer adenomas, associated with 5’ to 3’ mutations of APC gene
MAP- recessive inheritance, same clinical feature of AFAP
What is a CHRPE
Pigmented spot at the back of the eye
4 or more is dangerous
Outline the process of carcinogenesis
Uncontrolled proliferation of cells that leads to tumour formation
How can radiation lead to cancer?
DNA bases targeted by high energy radiation in high doses, eg. UV, Xray, Gamma rays
How can chemicals lead to cancer?
Bases in DNA damaged by oxidising/ alkylating agents.
Chemicals bind covalently to DNA to form DNA Adducts, causing cancer at particular sites
How can viruses lead to cancer?
Virus genome inserts near a host proto-oncogene causing overexpression and insertion of oncogene into host DNA
List the local effects of cancer
Pressure on the tissues Obstruction in hollow tissues Tissue ulceration Bleeding (haemorrhage) Pain Side effects of treatment
How may pain be caused from a cancer
Pressure on nerves Perineural infiltration (along fibre) Bone pain (weaker)
List the systemic effects of cancer
Abnormal secretion of hormones (non- endocrine site)
Cachexia - severe unwanted weight loss
Paraneoplastic syndromes
Identify the concept of dysplasia
Pre-malignant change (earliest visualised)
Identified in epithelium
No invasion (till cancer)
Dis-organisation of cells
What features do disorgansied cells have
Increased nuclear activity
Increased mitotic activity
Abnormal mitoses
Explain the role of growth factors in the promotion of tumours
Polypeptide molecules that regulate cell growth and function
Bind to cell membrane receptors
Stimulate activation of intacellular signal transduction
Contrast autocrine and paracrine growth factors
Autocrine - cell carries receptor and secretes GF
Paracrine - GFs produced by neighbouring cells
List the characteristics of benign tumours
Non-invasive growth factor
Usually encapsulates
No evidence of invasion/ metastasis
Cells similar to normal with similar function
List the characteristics of malignant tumours
Invasive growth pattern No capsule Abnormal cells Loss of normal function Evidence of spread
Describe the process of metastasis
Tumour invades through basement membrane
Moves into extracelular matrix, connective tissue or cells
Invades blood vessels to other organs
What are the most common sites of metastasis
Liver and bone marrow
Describe the process of metastasis in blood vessels
Adherence of tumour cells to blood vessels Invasion from blood vessels Invasion into tissue Formation of metastasis Clinical evidence
Describe the process of metastasis in lymphatic vessels
Adherence of tumour cells to lymph vessels endothelium Invasion from lymphatics Invasion into lymph node Formation od metastasis in lymph node Clinical evidence
Describe the process of metastasis in by trans-coelomic spread
Spread of tumour cells across body cavities eg. pleural/ peritoneal
Rapid screening
Which tumours spread by trans-coelomic
Lung, stomach, colon, ovary
