Mass Spec & Tumor markers Flashcards
What is mass spectrometry (MS)?
A powerful analytical technique used to identify unknown compounds, determine concentrations of known substances, and study molecular structure and chemical composition.
MS can detect drugs, steroids, damaged genes, dioxin, proteins, and metabolites.
What are the three main components of a mass spectrometer?
- Ionization source
- Mass analyzer
- Ion detection system
What is the role of the ionization source in mass spectrometry?
Converts molecules to gas phase ions that are manipulated by a magnetic field into the mass analyzer.
What techniques are used for ionization in mass spectrometry?
- Electron ionization
- Chemical ionization
- Electrospray ionization
- Matrix-assisted laser desorption/ionization (MALDI)
What does the mass analyzer do?
Sorts ions based on their mass to charge ratio (m/z).
What is the mass to charge ratio (m/z)?
The mass to charge ratio is obtained by dividing the atomic or molecular mass of an ion by the number of charges the ion bears.
How is a mass spectrum plotted?
Mass to charge ratio is plotted along the x-axis and the relative abundance is on the y-axis.
What is the purpose of combining mass spectrometry with separation techniques?
Aids in substance identification by allowing for better analysis of complex samples.
What does MALDI stand for?
Matrix-assisted laser desorption ionization.
What is the purpose of the MALDI technique?
To ionize samples for mass spectrometry analysis.
What is the function of the TOF mass analyzer?
Determines m/z ratios by measuring the time it takes ions to travel to the detector.
What is diagnostic sensitivity?
A measure of how often an assay detects a biomarker when the disease is present.
What is diagnostic specificity?
The probability that a laboratory test will be negative in the absence of disease.
What does Bayes’ theorem help calculate?
Updates the probabilities of hypotheses when given evidence.
What are tumor markers?
Measurable biochemicals associated with malignancy, produced by tumor cells or in response to them.
What is the main use of tumor markers in clinical practice?
Support diagnosis and monitor treatment response.
What are the advantages of using tumor markers?
- Aid in cancer diagnosis
- Monitor treatment response
- Serve as prognostic indicators
- Indicate relapse
What are some disadvantages of tumor markers?
- High variability in patient samples
- Lack of reliability
- Presence in non-cancerous conditions
What is alkaline phosphatase (ALP)?
An enzyme responsible for dephosphorylating compounds, primarily sourced from liver, bone, and intestine.
What conditions may elevated ALP indicate?
- Liver cancer
- Osteoblastic lesions related to prostate cancer
- Breast cancer with bone metastases
What is the role of creatine kinase (CK)?
Plays a role in energy production by catalyzing the conversion of creatine and using ATP to create phosphocreatine.
What conditions may elevated CK indicate?
- Small cell lung carcinoma
- Prostate cancer
What is Creatine Kinase (CK)?
Enzyme that plays a role in energy production, catalyzes the conversion of creatine and uses ATP to create phosphocreatine.
Principal sources are high energy tissues like heart muscle and brain.
What conditions can elevated Creatine Kinase (CK) indicate?
- Small cell lung carcinoma
- Prostate cancer
What is Lactate Dehydrogenase (LDH)?
Enzyme that catalyzes the interconversion of pyruvate and lactate with concomitant interconversion of NADH and NAD+.
What does elevated LDH indicate?
- Liver cancer
- Non-Hodgkins lymphoma
- Acute leukemia
- Nonseminomatous germ cell testicular cancer
- Seminoma
- Neuroblastoma
What role do hormones play as tumour markers?
Tumours of specific endocrine glands may produce elevated levels of specific hormones, useful for monitoring therapy or disease recurrence.
What is β-human chorionic gonadotropin?
Hormone secreted by normal placental tissue, elevated in trophoblastic tumours and certain cancers.
What conditions can elevated β-human chorionic gonadotropin indicate?
- Trophoblastic tumour
- Nonseminomatous testicular tumours
- Seminoma
- Melanoma
- Breast cancer
- GI cancer
- Lung cancer
- Ovarian cancer
What is Calcitonin?
Hormone produced by the thyroid for calcium homeostasis.
What can elevated Calcitonin levels indicate?
- Family medullary carcinoma of the thyroid
- Carcinoid tumours
- Lung cancer
- Breast cancer
- Kidney cancer
- Liver cancer
What is Adrenocorticotropic hormone?
Hormone produced by corticotrophic cells of the anterior pituitary gland that controls cortisol production.
What conditions can elevated Adrenocorticotropic hormone indicate?
- Small cell lung carcinoma
- Pancreatic cancer
- Breast cancer
- Gastric cancer
- Colon cancer
What is Alpha fetoprotein (AFP)?
Protein normally produced by the fetal yolk sac and hepatic cells, used as a tumour marker.
What conditions can elevated AFP indicate?
- Hepatocellular carcinoma
What is Prostate specific antigen (PSA)?
Protein found in the epithelial cells of the prostate gland, used for detecting prostate cancer.
What are some clinical uses of PSA?
- Detect early stage prostate cancer
- Evaluate disease progression
- Assess therapeutic response
- Identify post-surgical residual disease
What is CA 15-3?
Type of mucin often overexpressed on malignant glandular cell surfaces, used as a breast cancer marker.
What is HER2-neu?
Epidermal growth factor receptor that, when amplified in cancer, causes uncontrolled cell growth.
What is CA 549?
Glycoprotein that may be elevated in breast cancer and non-breast metastatic carcinoma.
What is CA 27.29?
Mucin biomarker associated with metastatic breast cancer, useful for detection of recurrence.
What is CA125?
Glycoprotein expressed by epithelial ovarian tumours, used for monitoring recurrence of ovarian cancer.
What are some biomarkers for ovarian cancer?
- Eosinophil-derived neurotoxin (EDN)
- Osteopontin fragments
- IL-6
- IL-8
- VEGF
- EGF
- Kallikreins
- Plasmalogens
- Lysophosphatidic acid
What is Carcinoembryonic Antigen (CEA)?
Family of cell surface glycoproteins elevated in various cancers, used primarily for monitoring therapy.
What is Guanylyl Cyclase C (GC-C)?
Receptor expressed in intestinal mucosal cells, detection in blood may indicate cancerous growth.
What is CA 19-9?
Tetrasaccharide that is a derivative of the Le a blood group antigen, useful for determining recurrence of pancreatic cancer.
What is CA 50?
Monoclonal antibody developed against colon adenocarcinoma, elevated levels occur in pancreatic cancer.
What is CA 242?
Monoclonal antibody developed from colorectal carcinoma cell line, recognized epitopes of CA 50 and CA 19-9.
What is Bladder Tumour Antigen (BTA)?
High molecular weight polypeptide found in urine due to tumour invasion or production.
What is Nuclear matrix protein-22 (NMP-22)?
Nuclear mitotic apparatus protein released during apoptosis, levels are significantly higher in bladder cancer.
What is Neuron Specific Enolase (NSE)?
Glycolytic enzyme found in neuronal tissue, elevated levels correlate with cancer stages.
What is CYFRA 21-1?
Cytokeratin marker useful for detecting non-small cell lung carcinoma.
What is Squamous Cell Carcinoma Antigen (SCCA)?
Glycoprotein with good specificity for small cell lung carcinoma.
What is CA 72-4?
Mucin detected by monoclonal antibody B72-3, used for gastric cancer diagnosis.
What is the role of CA 125 in gallbladder cancer?
Useful as a diagnostic measure in preoperative evaluation.
What is the significance of biochemical tumour markers?
Provide information for screening, diagnosis, prognosis, monitoring, and recurrence detection.
What technologies are used for tumour marker analysis?
- Molecular diagnostic techniques
- Genetic assays
- Mass spectrometry
