1、Figure: Amplification of the EGFR gene in human breast carcinoma. The EGFR gene, becomes amplified and is seen either as extra chromosomal double minutes or as a chromosomally integrated, homogeneously staining region.,Adapted from Robbins Basic Pathology,EGFR,Insensitivity to growth-inhibitory sign

2、als: tumor suppressor genes The proteins that apply brakes to cell proliferation are the products of tumor suppressor genes, which can be inactivated by epigenetic (表觀遺傳學(xué)，gene hypermethylation) and genetic alterations (gene mutation/deletion). TP53: mutation P16: gene hypermethylation or mutation PT

3、EN: mutation,Figure: genetic gene silencing,Figure: the dynamics of epigenetic gene silencing,Figure: epigenetic silencing,Epigenetics affects genes expression tumor suppressor genes, such as p16 (INK4a), p15 (INK4b), p14 (ARF) and adenomatous polyposis coli (APC) DNA repair genes, such as human Mut

4、 L homologue 1 (hMLH1), glutathione S-transferase P1 (GSTP1，谷胱甘肽S-轉(zhuǎn)移酶P1 ) and O6-methylguanine-DNA methytransferase (MGMT) genes related to metastasis and invasion, such as E-cadherin (CDH1), tissue inhibitor of metalloproteinase-3 (TIMP3) and death associated protein kinase (DAPK),Epigenetics affec

5、ts genes mutation Cytosine methylation in the coding region of genes can increase mutation rates because of the spontaneous hydrolytic deamination of methylated cytosine, which causes C to T transition mutations at methylated CpG sites. Methylation also changes the absorption wavelength of cytosine,

6、 into the range of incident sunlight, resulting in CC to TT mutations, which commonly occur in skin cancers. Methylated CpGs are also preferred binding sites for benzo(a)pyrene diolepoxide (環(huán)氧化物苯并芘) and other carcinogens that are found in tobacco smoke. These cause DNA adducts and G to T transversio

7、n mutations, which are often found in the aerodigestive tumours of smokers.,Figure: The role of p53 in maintaining the integrity of the genome.,The role of p16, which is inactivated by gene mutation or promoter hypermethylation,PI3K:磷脂酰肌醇-3-激酶 PIP2:磷酯酰肌醇-4,5-二磷酸 PIP3:磷酯酰肌醇-3,4,5-三磷酸,Defects in DNA r

8、epair DNA damage from environmental agents DNA alterations resulting from errors that occur spontaneously during DNA replication,Defects in three types of DNA repair systems: mismatch repair Germ line mutations in the MSH2 (2p16) and MLH1 (3p21) genes each account for approximately 30% of Hereditary

9、 Nonpolyposis Cancer Syndrome. nucleotide excision repair Xeroderma Pigmentosum recombination repair Germ line mutation of Brcca1 and Brca2 in breast cancer,mismatch repair,Excision repair,Excision repair,recombination repair,Interacting proteins of Brca1 and Brca2,綠色：基因滅活表現(xiàn)為基因突變 紅色：基因滅活表現(xiàn)為基因甲基化 紫色：

10、基因滅活表現(xiàn)為基因突變和甲基化,The molecular basis of cancer,Evasion of apoptosis Accumulation of neoplastic cells may occur not only by the activation of oncogenes or inactivation of tumor suppressor genes, but also by mutations in the genes that regulate apoptosis.,Figure: The extrinsic (death receptor-initiated

11、) pathway of apoptosis, illustrated by the events following Fas engagement.,Figure: The intrinsic (mitochondrial) pathway of apoptosis. Death agonists cause changes in the inner mitochondrial membrane, resulting in the mitochondrial permeability transition (MPT) and release of cytochrome c and other

12、 pro-apoptotic proteins into the cytosol, which activate caspases.,Limitless replicative potential: telomerase (端粒酶) Telomerase activity and maintenance of telomere length are essential for the maintenance of replicative potential in cancer cells.,The molecular basis of cancer,The telomere-telomeras

13、e hypothesis - changes in telomere length are detected in germ cells, stem cells, somatic cells, and tumor cells.,The molecular basis of cancer,Development of sustained angiogenesis Tumors stimulate the growth of host blood vessels, a process called angiogenesis (血管生成), which is essential for supply

14、ing nutrients to the tumor. Tumor-associated angiogenic factors are produced by tumor cells or may be derived from inflammatory cells (e.g., macrophages) that infiltrate tumors. Of the dozen or so known tumor-associated angiogenic factors, the two most important are vascular endothelial growth facto

15、r (VEGF,血管內(nèi)皮生長因子) and basic fibroblast growth factor (bFGF,堿性纖維母細(xì)胞生長因子).,Ability to Invade and Metastasize Invasion and metastasis are biologic hallmarks of malignant tumors. They are the major cause of cancer-related morbidity and mortality and hence are the subjects of intense scrutiny. The metast

16、atic cascade can be subdivided into two phases: invasion of extracellular matrix (ECM,細(xì)胞外基質(zhì)) vascular dissemination and homing of tumor cells.,Invasion of extracellular matrix Invasion of the ECM is an active process that is accomplished in four steps: Detachment (loosening up) of the tumor cells fr

17、om each other Attachment of tumor cells to matrix components Degradation of ECM Migration of tumor cells,Membranous E-cadherin ； Membranous b-catenin ； Cytoplasmic or nuclear b-catenin Intergrin ； MMP-2 ； MMP-9 Figure: Schematic illustration of the sequence of events in the invasion of epithelial ba

18、sement membranes by tumor cells.,Figure: The role of APC in regulating the stability and function of -catenin. APC and -catenin are components of the WNT signaling pathway. In resting cells, -catenin forms a macromolecular complex containing the APC protein. This complex leads to the destruction of

19、-catenin. B, When cells are stimulated by secreted WNT molecules, the destruction complex is deactivated, -catenin degradation does not occur. -catenin translocates to the nucleus, where it binds to TCF, a transcription factor that activates several genes involved in the cell cycle. C, When APC is m

20、utated or absent, the destruction of -catenin cannot occur. -Catenin translocates to the nucleus and coactivates genes that promote the cell cycle, and cells behave as if they are under constant stimulation by the WNT pathway.,Adapted from Robbins Basic Pathology,Adapted from Robbins Basic Pathology

21、,Metastatic tumor: VEGF bFGF E-cadherin,Carcinogenesis is a multistep process,Laboratory diagnosis of breast cancer Morphologic methods Cytologic Diagnosis Histologic Diagnosis Detection of molecular markers Immunoperoxidase Techniques Flow Cytometry FISH microarray,Part 3,Cytologic Diagnosis Cytolo

22、gic examination of cells is a useful and accurate method of diagnosing cancer. The general rule that cytologic diagnosis must be confirmed by histologic diagnosis before radical treatment is undertaken has been modified as confidence in cytologic and immunohistochemical techniques has grown.,Techniq

23、ues of Cytologic Diagnosis Exfoliated cells can be identified in samples of nipple discharge. Fine-needle aspiration (FNA): Cells obtained are smeared on slides for cytologic examination. Ultrasonography may help guide the needle into the mass.,Histologic Diagnosis Histologic diagnosis is considered

24、 the definitive method of establishing the diagnosis of a neoplasm. The diagnosis may be based on examination of the entire neoplasm removed at surgery (excisional biopsy) or examination of a sample of the neoplasm obtained either by incisional biopsy or with a large-bore cutting needle.,乳腺癌相關(guān)的分子標(biāo)志物

25、,家族性乳腺癌的風(fēng)險預(yù)測 Brca1 Brca2 P53 PTEN 乳腺癌的診斷和治療 激素治療：ER、PR 靶向治療：Her2 化療：21基因檢測 分子分型,Immunoperoxidase Techniques Immunohistochemical stains use specific labeled antibodiesusually horseradish peroxidaseto identify marker antigens in cells and tissues. When the peroxidase label reacts with a substrate, it

26、produces a colored product that identifies the location of the antigen in the tissues.,Figure. Predictive markers. A, Estrogen receptor is detected in the nucleus by immunohistochemical studies. Progesterone receptor has the same appearance. B, HER2/neu overexpression is detected on the cell membran

27、e by immunohistochemistry. C, Amplification of the HER2/neu gene can be detected by FISH analysis with a fluorescent probe for the gene. A normal cell has two copies of the gene. These tumor cells have over 25 signals, indicating amplification of the gene for HER2/neu.,(A) Non-amplified tumour. (B)

28、High level HER2 gene amplification as the HER2/CEP17 ratio is greater than 2.2 (C) Low level HER2 gene amplification.,the HER-2/neu gene signal is red chromosome 17 centromere is green,FISH detection of HER-2/neu oncogene in invasive breast carcinomas,A,B,C,Flow Cytometry Flow cytometry can rapidly

29、and quantitatively measure several individual cell characteristics, such as membrane antigens and the DNA content of tumor cells. A relationship between abnormal DNA content and prognosis is becoming apparent for a variety of malignancies. In general, aneuploidy seems to be associated with poorer prognosis in early-stage breast cancer.,Molecular profiling of tumors DNA microarray analysis: Thi