BMS314 Lecture Notes - Lecture 27: Hypertrophic Cardiomyopathy, Inflammatory Bowel Disease, Cytotoxic T Cell
What is neoplasia?
• Basic concepts, terms and definitions
• Benign vs Malignant
• Cells of Origin
This lecture covers
• some important concepts underpinning an understanding of neoplasia.
• The factors affecting the growth of a cell population will be revisited
• a brief overview of the definitions of other key terms and processes such as
hyperplasia, hypertrophy, atrophy, metaplasia and dysplasia.
• This section tackles the problem of adequately defining neoplasia by reviewing various
definitions.
• The potential sources of neoplastic cells within an organ are reviewed. -
• A key component is the understanding of what is meant by ‘benign’ and ‘malignant’ with
respect to neoplasms.
• The principles of nomenclature of neoplasms are outlined using as examples the three
basic tissue origins: mesenchymal, epithelial and round cell.
• Exceptions to standard nomenclature are many, and specific examples are illustrated.
Why do you think it matters whether a cell population has “excessive and unregulated
proliferation that becomes autonomous”?
i.e. why does neoplasia matter? Why do we want to know whether something is
neoplastic or not?
• Neoplasia can be a continuum of adaptive tissue response changes
• A tumour isn't always neoplasia
• Not all masses are neoplastic
• Clonal = identical
• What differentiates neoplasia from all other tumors is the excessive unregulated
proliferation that becomes autonomous
o Normally when something goes out of control the body has mechanisms to
control and stop this
• i.e. once the stimulus that makes it grow is gone, or some anti-tumor
mechanisms are put in place, the tumor will get smaller and go away
o However with neoplasms this doesn’t occur, they just continually grow
without any control
• Evading growth suppressors
o Immune to substances like hormones, cytokine etc. which would normally
come in and tell it to stop growing
• Activating invasion and metastasis
o Enabling the tumour to invade the tissue around it and spread to different
sites (like an infectious organism)
• Enabling replicative immortality
o Evading the death of telomeres which are responsible for cell replication
• Inducing angiogenesis
o All tissues in the body need a blood supply, neoplasia's can induce the
formation of a new blood supply to prevent it from dying
• Resisting cell death
o Tumours often don’t undergo apoptosis
• Sustaining proliferative signalling
o Something in there telling it to grow
Finding a satisfactory and concise definition of neoplasia reflects a deep understanding
of what the process is, so review these definitions at the end of the course, and try to
decide if they accurately reflect your understanding of neoplasia. Search for other
definitions, and critically review their accuracy and clarity. Note that oncology is the
study of neoplasia (onco meaning neoplasia and logy meaning study), and neoplastic
cells are often termed transformed cells (the process being termed transformation). It is
important to note when discussing neoplasia that the word tumour often denotes those
forms of neoplasia that have an ‘abnormal swelling or enlargement’, however we will
soon find out that not all neoplasms form tumours (e.g. haemopoietic neoplasms –
leukaemias. As a simple of a word neoplasia may sound, coming up with the best
Document Summary
What is neoplasia: basic concepts, terms and definitions, benign vs malignant, cells of origin. Finding a satisfactory and concise definition of neoplasia reflects a deep understanding of what the process is, so review these definitions at the end of the course, and try to decide if they accurately reflect your understanding of neoplasia. Search for other definitions, and critically review their accuracy and clarity. Note that oncology is the study of neoplasia (onco meaning neoplasia and logy meaning study), and neoplastic cells are often termed transformed cells (the process being termed transformation). As a simple of a word neoplasia may sound, coming up with the best definition is often tedious. Please see below for additional definitions that may prove useful for you. Neos = new, plasma = formation (lennox, 1980). New, abnormal growth with uncontrolled, progressive cell multiplication (bailli re"s comprehensive veterinary dictionary 1988). New and abnormal growth or formation of tissue; a tumour (shorter.
