Neoplasia
Genotypic alteration leading to phenotypic change in cell behaviour/appearance; ie cells that grow abnormally, literally "new growth"
Progressive genetic change (normal --> metaplasia --> dysplasia --> progressive anaplasia --> neoplasia)
Benign tumor
Growth limited to a specific site that does not spread in a non-contiguous manner, often encapsulated, cells are differentiated and resemble surrounding tissue.
Characterised by uniform cell populations, normal number of chromosomes, and normal cell funct
Malignant tumor
Mutations resulting in cells that spread in a non-contiguous manner, lacks capsule and not clearly separated from normal tissue.
Characterised by anaplastic undifferentiated cells that exhibit features not inherent to tissue of origin, pleomorphism (heter
Dysplasia
Abnormal, non-malignant growth. Somewhere between normal cell growth and neoplasia
Anaplasia
Cells that are undifferentiated / have lost their defining characteristics.
- pleomorphic
- abnormal nucleus
- numerous mitosis
- loss of normal structure
Metastasis
Secondary, malignant tumors that are discontinuous from primary tumor and can spread to other sites in the body through the lymphatic system, via blood (hematogenous spread), and seeding of body cavities.
Carcinoma
Metastatic cancer of epithelial origin
Sarcoma
Metastatic cancer of connective tissue origin
Oncogene
Gene that causes manifestation of malignant phenotype(s), often associated w/ RNA viruses
Three Types
1) v-onc: associated w/ retroviruses (rv = contain only exons, encoding for protein sequence)
2) c-onc: proto-oncogenes
3) cellular oncogene: contains ex
Exon
Encode for mRNA / protein
Intron
Does not encode for a protein
Dominant allele
Allele whose phenotype will manifest in heterozygous state, affecting both males and females.
- at least one parent has copy of gene and offspring have 50% chance of receiving
- symptoms vary based on penetrance (mathematical likelihood of expression) & e
Recessive allele
Allele whose phenotype will manifest only in homozygous state.
- both parents must have (even if unexpressed) and offspring have 25% chance of receiving two copies of gene (required for expression)
- largest category and includes almost all inborn errors
X-linked disorder
Recessive allele carried only on the X chromosome so conditions almost exclusively affect males, very seldom seen in women
Phenylketonuria
Autosomal recessive inability to convert phenylalanine to tyrosine resulting in accumulation of phenylalanine that leads to cognitive impairment
Normal pts use 50% of phenylalanine for protein synthesis and convert the other 50% to tyrosine
Teratogen
Agent that causes fetal abnormalities
1) X-rays
2) Chemotoxins: alcohol, drugs, certain chemicals
3) Microbes: TORCH viruses (toxoplasmosis, other, rubella, cytomegalovirus, herpes)