Colorectal serrated pathway cancers and precursors

The serrated pathway (SP) can be viewed as two parallel, but partially overlapping, arrays of colorectal precursor lesions, and their respective endpoint carcinomas, that are distinct from those of the conventional adenoma–carcinoma sequence (APC‐pathway). In this review we focus at the outset on the clinical impact, pathological features, molecular genetics and biological behaviours of the various SP cancers. Then we summarize the clinicopathological features, classification and molecular profiles of the two main precursor lesions that anchor the respective pathways: (i) sessile serrated adenoma/polyp (SSA/P), also called sessile serrated lesion (SSL), and (ii) traditional serrated adenoma (TSA). Activating mutations of the RAS–RAF–MAPK pathway initiate and sustain the lesions of the SP, and CpG island methylation of the promoter regions of tumour suppressor and DNA repair genes play the major role in their neoplastic progression. The SP includes microsatellite stable (MSS) carcinomas that are among the most biologically aggressive colorectal carcinomas (CRC), and also accounts for the great preponderance of sporadic hypermutated, mismatch repair (MMR)‐deficient or microsatellite instable (MSI) CRC. The identification, removal and appropriate classification of at‐risk SP precursors and surveillance of individuals who harbour these lesions present a challenge and opportunity for CRC prevention and mortality reduction.     

微卫星改变与肺癌发生发展的关系

目的 :研究肺癌组织中第 3号染色体短臂 (3P)和第 9号染色体短臂 (9P)上微卫星标志物的改变与肺癌发生发展的关系。方法 :应用聚合酶链反应 (PCR)结合微卫星银染法检测 5 6例肺癌和 2 3例良性肺部病变 3P和 9P上的微卫星标志物的改变。结果 :5 6例肺癌组织标本中 3P上有微卫星改变 2 6例 ,检出率 46% ,9P上有微卫星改变的 2 3例 ,检出率为 41% ,5 6例肺癌组织中 ,3P和 9P上有微卫星改变的 3 9例 ,检出率 69 6% ,2 3例肺部良性疾病组织中均未出现微卫星标志物改变。肺癌组织标本中 3P上的微卫星改变与肺癌的分化程度有关 ,低分化肺癌的微卫星改变较高、中分化肺癌的微卫星改变明显增多 (P <0 .0 1)。而 9P上的微卫星改变与淋巴结转移有关 ,有淋巴结转移的肺癌组织标本上微卫星改变较不伴淋巴结转移的微卫星改变检出率明显增多 ,(P <0 .0 5 )。结论 :3P和 9P上的微卫星改变与肺癌发生、发展和转移密切相关 ,检测肺癌组织 3P和 9P上的微卫星改变对肺癌的早期诊断和判断有无淋巴结转移有一定的价值     

胃癌及肠化组织的微卫星不稳定性

目的 :探讨微卫星不稳定性 (MSI)在胃癌及肠化组织中的发生规律及其在胃癌发生过程中的作用。方法 :对 30例胃癌、4 0例肠上皮化生的石蜡标本分别提取病变及相应正常组织的DNA ,应用银染PCR SSCP技术检测 5个微卫星位点的不稳定性。结果 :胃癌组织MSI的发生率为2 3 3% ,胃窦癌MSI的发生率显著高于贲门癌 (P =0 0 4 4 )。肠化组织MSI发生率 2 0 % ,MSI全部出现在中度以上肠化组织中 (P =0 0 13) ,且更多见于女性 (P =0 0 4 4 )。结论 :MSI是胃癌多步骤发生过程中的早期分子事件 ,在胃癌的发生中可能具有重要作用。     

中国人D13S301位点的微卫星多态及其应用价值

率先在国内应用ＰＣＲ技术扩增Ｗｉｌｓｏｎ病（ＷＤ）基因内部Ｄ１３Ｓ３０１位点的微卫星多态，通过变性聚丙烯酰胺凝胶电泳检测扩增产物，对８０名正常中国人进行了检测，结果具有１２种不同长度的等位片段，多态信息含量（ＰＩＣ值）为０．８８３，表明该位点在中国人群中具有长度多态性及较高的应用价值。应用该位点对１０个ＷＤ家系进行连锁分析，在２４名无症状个体中检出１２名基因携带者，７名正常纯合子及２名症状前患者，进一步证实该位点可用于ＷＤ的症状前诊断及杂合子筛选。     

胃腺癌微卫星不稳定性与VEGF蛋白表达关系的研究

目的：探讨胃癌微卫星不稳定性(MSI)与胃腺癌中皿管内皮生长因子(VEGF）之间的关系。方法：应用PCR—SSCP技术检测30例胃腺癌5个位点的微卫星不稳定性，同时应用免疫组织化学的方法检测肿瘤皿管内皮生长因子(VEGF)蛋白的表达。结果：MSI阳性率为43．4％(13／30)。VEGF阳性率为60％(18／30）。MSI—H胃癌VEGF的表达显著减少。结论：MSI—H的胃癌与MSS胃癌可能存在两种不同的胃癌及肿瘤血管新生形成的途径。MSI—H肿瘤较低的VEGF表达可能可以解释为何MSI-H胃癌有较低的侵袭性。     

Integrinα4在骨肉瘤中的表达与意义

Objective： To investigate the expression of integrin α4 in osteosaxcoma and significance. Methods- Forty-six patients with osteosarcoma （Enneking Ⅰ-Ⅲ） were analyzed for the expression of α4 integrin subunit using immunohistochemical method. Results： Twenty-nine （63.04%） of 46 samples demonstrated positive （＋-＋＋） integrin α4 expression. Loss expression of integrin α4 was observed in the patients with advanced Enneking stage （P=0.0040） and with metastatic disease at presentation （P=0.0158）. Integrin α4 expression correlated with cell differentiation, the level of malignancy and the invasive behavior of osteosaxcoma. Conclusion： The loss expression of integrin α4 subunit might be a predictor indicating the invasive potential of osteosarcoma and play a role in metastasis of osteosaxcoma patients.     

Microsatellite analysis of breast carcinoma and corresponding local recurrences

Local recurrence is a serious complication of breast carcinoma that reduces quality of life and influences prognosis. The aim of this study was to determine whether local recurrences of breast carcinoma are genetically related to the primary tumours. Forty cases of locally recurrent breast carcinomas (median onset: 3.6 years after primary surgery) were analysed: 22 patients had undergone breast-conserving therapy and 18 mastectomy. Eighteen microsatellites on chromosomes 2p, 3p, 5q, 10q, 11p, 11q, 13q, 17q, 17p, 18p were amplified by PCR using fluorescent-labelled primers, automatically detected after polyacrylamide gel electrophoresis and analysed for loss of heterozygosity (LOH) or microsatellite instability (MSI). Follow-up data were available for 39 cases with a median value of 89 months. All LOH and MSI found in the primary tumours were also present in the corresponding recurrences, indicating that they are genetically related to the primary tumours and not secondary malignancies in the same breast. MSI was found in three cases, of which one harboured MSI at more than two loci. The median value of LOH per case was significantly higher in the recurrent (four per case) compared to the primary tumours (two per case; p < 0.001, Mann-Whitney test), reflecting the genotype of tumour progression. Early local recurrence was associated with specific LOH for TP53.15 (p = 0.018, log-rank test) in the primary tumours. LOH on D13S1699 or D17S855 was associated with lymph node metastases (p = 0.024 and p = 0.019, respectively; chi-square test). In addition, tumour grade, lack of oestrogen or progesterone receptor expression, young patient age and early appearance of local recurrence significantly correlated with poor survival. The development of local recurrence despite clear resection margins may result from residual DCIS distant from the invasive carcinoma, homing of circulating tumour cells, or genetically altered, histologically normal breast tissue not immediately adjacent to the invasive carcinoma.