Podcast
Questions and Answers
What is a characteristic feature of neoplasms?
What is a characteristic feature of neoplasms?
Which factor does NOT typically influence the incidence of cancer?
Which factor does NOT typically influence the incidence of cancer?
How are familial cancers typically characterized in comparison to sporadic cancers?
How are familial cancers typically characterized in comparison to sporadic cancers?
What type of genetic lesion can contribute to malignancy through deletion?
What type of genetic lesion can contribute to malignancy through deletion?
Signup and view all the answers
Which of the following is NOT a means by which tumor cells acquire mutations?
Which of the following is NOT a means by which tumor cells acquire mutations?
Signup and view all the answers
What role do miRNAs play in carcinogenesis?
What role do miRNAs play in carcinogenesis?
Signup and view all the answers
What is a result of balanced translocations in tumor cells?
What is a result of balanced translocations in tumor cells?
Signup and view all the answers
What type of changes can silence tumor suppressor genes?
What type of changes can silence tumor suppressor genes?
Signup and view all the answers
What is the characteristic feature of benign tumors compared to malignant tumors?
What is the characteristic feature of benign tumors compared to malignant tumors?
Signup and view all the answers
Which statement correctly describes tumor suppressor genes?
Which statement correctly describes tumor suppressor genes?
Signup and view all the answers
Which of the following is NOT a characteristic of malignant tumors?
Which of the following is NOT a characteristic of malignant tumors?
Signup and view all the answers
In what way do benign tumors differ morphologically from their malignant counterparts?
In what way do benign tumors differ morphologically from their malignant counterparts?
Signup and view all the answers
Which of the following is a sign of malignancy in tumor histology?
Which of the following is a sign of malignancy in tumor histology?
Signup and view all the answers
Which acquired preneoplastic disorder is characterized by persistent regenerative cell replication?
Which acquired preneoplastic disorder is characterized by persistent regenerative cell replication?
Signup and view all the answers
What is the general naming convention for benign tumors?
What is the general naming convention for benign tumors?
Signup and view all the answers
Which feature is commonly associated with the malignancy of tumors?
Which feature is commonly associated with the malignancy of tumors?
Signup and view all the answers
What is a key characteristic of dysplasia in cells?
What is a key characteristic of dysplasia in cells?
Signup and view all the answers
Which process is NOT a pathway for metastasis?
Which process is NOT a pathway for metastasis?
Signup and view all the answers
In which type of tumors is hæmatogenous spread most typical?
In which type of tumors is hæmatogenous spread most typical?
Signup and view all the answers
What is the first step in the invasion of ECM by tumor cells?
What is the first step in the invasion of ECM by tumor cells?
Signup and view all the answers
What is a consequence of hypoxia in tumor growth?
What is a consequence of hypoxia in tumor growth?
Signup and view all the answers
What occurs during the process of intravasation by tumor cells?
What occurs during the process of intravasation by tumor cells?
Signup and view all the answers
Which statement about the role of p53 in angiogenesis is accurate?
Which statement about the role of p53 in angiogenesis is accurate?
Signup and view all the answers
What is the hallmark of malignancy related to tissue invasion?
What is the hallmark of malignancy related to tissue invasion?
Signup and view all the answers
What is the primary function of proteolytic enzymes secreted by tumor and stromal cells?
What is the primary function of proteolytic enzymes secreted by tumor and stromal cells?
Signup and view all the answers
Which organ is most commonly the site of arrest for metastatic tumors?
Which organ is most commonly the site of arrest for metastatic tumors?
Signup and view all the answers
Which of the following is NOT a characteristic of benign tumors?
Which of the following is NOT a characteristic of benign tumors?
Signup and view all the answers
What is a characteristic feature of malignant tumors compared to benign tumors?
What is a characteristic feature of malignant tumors compared to benign tumors?
Signup and view all the answers
What type of tumor is defined by divergent differentiation into all embryonic layers?
What type of tumor is defined by divergent differentiation into all embryonic layers?
Signup and view all the answers
Which sampling approach is NOT mentioned as a method for tumor diagnosis?
Which sampling approach is NOT mentioned as a method for tumor diagnosis?
Signup and view all the answers
How are tumor markers used in cancer management?
How are tumor markers used in cancer management?
Signup and view all the answers
Which type of tumor originates from epithelial tissue?
Which type of tumor originates from epithelial tissue?
Signup and view all the answers
Study Notes
Neoplasia
- New or abnormal tissue growth, uncontrolled by normal tissue growth factors.
- Continues to replicate even after the stimulus for growth ceases.
- Competes with normal cells and tissues for resources.
- Shows autonomy, growing independently of its environment.
- Often requires endocrine stimuli for growth.
Epidemiology of Cancer
- Incidence varies with age, race, geographic location, and genetics.
- Most common in very young and elderly individuals.
- Geographic variation primarily due to environmental exposures.
- Most cancers are sporadic, but some are familial.
- Hereditary cancers can be autosomal dominant or autosomal recessive.
- Autosomal dominant cancers linked to germline mutations in tumor suppressor genes.
- Autosomal recessive cancers associated with inherited DNA repair defects.
- Familial cancers are often bilateral and occur earlier in life than sporadic variants.
- Preneoplastic disorders are associated with increased cancer risk.
Genetic Lesions in Cancer
- Tumor cells acquire mutations through point mutations, translocations, deletions, and gene amplifications.
- Balanced translocations contribute to carcinogenesis by overexpressing oncogenes or creating fusion proteins with altered signaling.
- Deletions often target tumor suppressor genes.
- Gene amplifications increase oncogene expression.
- Overexpression of miRNAs can suppress tumor suppressors.
- Deletion or loss of miRNAs can lead to proto-oncogene overexpression.
- Epigenetic changes can silence tumor suppressor and DNA repair genes through promoter methylation.
Insensitivity to Growth Inhibitory Signals
- Tumor suppressor genes encode proteins that regulate cell cycle progression, inhibiting proliferation.
- Both copies of a tumor suppressor gene must be dysfunctional for tumor development.
- In familial cancers, individuals inherit one defective copy and lose the second through somatic mutation.
- In sporadic cancers, both copies are lost through somatic mutations.
Tumor Classification
- Neoplasms can be classified as benign or malignant.
- Benign tumors: Localized, non-invasive, and may cause local effects.
- Malignant tumors (cancers): Invade and destroy surrounding tissues, capable of metastasis.
Benign Tumors
- Resemble normal cells in morphology and function.
- Well differentiated cells.
- Mitosis is rare and normal.
- Slow growth, localized, non-infiltrative.
- Examples: fibroma, chondroma, leiomyoma, adenoma, papilloma, polyp, cystadenoma, fibroadenoma, pleomorphic adenoma.
Acquired Preneoplastic Disorders
- Persistent regenerative cell replication (e.g., chronic skin ulcers, liver cirrhosis).
- Hyperplastic and dysplastic proliferations (e.g., endometrial hyperplasia, bronchial dysplasia).
- Chronic atrophic gastritis.
- Chronic ulcerative colitis.
- Leukoplakia of the oral cavity.
- Villous adenomas of the colon.
Malignant Tumors
-
Characteristics:
- Pleomorphism: Variation in size and shape of cells.
- Hyperchromasia: Increased nuclear pigmentation.
- High nuclear to cytoplasmic ratio (N/C).
- Giant multinucleated cells.
- Nuclear pleomorphism with coarse chromatin.
- Numerous atypical mitoses.
- Loss of polarity: Disorganized cell orientation.
- Dysplasia: Loss of cellular uniformity and architecture within epithelium (carcinoma in situ).
-
Growth and Spread:
- Rapid growth, infiltrative, invasive, destructive.
- Metastasis: Formation of secondary implants distant from primary tumor.
- Metastatic pathways: Seeding within body cavities, lymphatic spread (carcinomas), hematogenous spread (sarcomas and some carcinomas).
Mechanisms of Local and Distant Spread
-
Invasion of extracellular matrix (ECM):
- Detachment of tumor cells from each other (loss of E-cadherins).
- Attachment to ECM components.
- Degradation of ECM by tumor cell-secreted proteases (MMPs).
- Migration of tumor cells guided by cytokines, matrix cleavage products, and growth factors.
-
Vascular Dissemination:
- Intravasation: Tumor cells penetrate blood vessel basement membranes, forming emboli.
- Extravasation: Emboli adhere to endothelium and migrate through the basement membrane.
Angiogenesis
- Tumor vascularization is essential for growth.
- Balance between pro-angiogenic and anti-angiogenic factors produced by tumor and stromal cells.
- Hypoxia triggers angiogenesis through HIF-1α and VEGF.
- p53 can inhibit angiogenesis.
Metastatic Site Prediction
- Metastatic site can often be predicted based on primary tumor location.
- Most tumors arrest in the first capillary bed encountered (lung and liver).
- Organ tropism may occur due to adhesion receptors or chemokines expressed at the metastatic site.
Nomenclature of Malignant Tumors
- Mesenchymal origin: Sarcomas (e.g., fibrosarcoma, chondrosarcoma, leiomyosarcoma).
- Epithelial origin: Carcinomas (e.g., squamous cell carcinoma, adenocarcinoma).
- Mixed origin (mesenchymal and epithelial): Teratomas (differentiate into all embryonic layers, found in ovaries and testes).
Benign vs. Malignant Tumor Characteristics
- Differentiation: Benign tumors are well differentiated, malignant tumors are poorly or undifferentiated.
- Growth Rate: Benign tumors are slow-growing, malignant tumors are fast-growing.
- Local Invasion: Benign tumors are well-circumscribed, malignant tumors invade surrounding tissues.
- Metastasis: Benign tumors are localized, malignant tumors metastasize to distant sites.
Laboratory Diagnosis of Cancer
- Sampling methods: Excision, biopsy, fine-needle aspiration, cytologic smears.
- Immunohistochemistry and flow cytometry: Used for diagnosis and classification, identify specific protein expression patterns.
- Tumor markers: Proteins released into the serum (e.g., PSA), aid in cancer screening and monitoring recurrence.
- Molecular analyses: Diagnose, predict prognosis, detect minimal residual disease, and identify hereditary predisposition to cancer.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the key concepts of neoplasia, including its definition and characteristics. This quiz also covers the epidemiology of cancer, examining how genetics and environmental factors influence cancer incidence across different demographics.
