罕见RET 原癌基因Y606C 突变所致家族性甲状腺髓样癌家系临床特点分析*

目的:分析讨论RET 原癌基因Y 606C 这一罕见突变所致家族性甲状腺髓样癌（familial medullary thyroid carcinoma ,FMTC）的临床生物学特点。方法:对先期确诊的1 个携带RET 原癌基因Y 606C 种系突变的FMTC 家系成员进行RET 基因种系突变筛查,同时行血清降钙素、甲状旁腺素、颈腹部超声等相关临床检查,对患病成员和携带者给予临床干预,并总结分析上述病例临床生物学特点。结果:包括先证者在内,该家系中10例参与基因筛查,发现6 例携带RET 基因第10外显子Y 606C 突变。其中3 例确诊为FMTC 患者（含先证者）,均为女性,平均发病年龄50.0（47～53）岁。发病成员临床均表现为甲状腺肿物伴降钙素升高,未发现甲状旁腺和肾上腺病变。2 例行全甲状腺切除术,1 例行患侧腺叶切除术。术后病理均确诊为甲状腺髓样癌,其中2 例病理分期均属早期,术后随访期间均达生化治愈。家系中另有3 例为突变携带者,平均年龄33.0（15～55）岁。其中2 例颈部超声均提示甲状腺肿物（考虑良性）,另1 例颈部超声未见异常。除1 例拒绝降钙素检测外,其余2 例血清降钙素均正常范围,建议定期复查。结论:RET 原癌基因Y 606C 突变可以导致FMTC 发病,家系成员发病平均年龄较大,肿瘤分期较早,生化治愈率高,预后较好;家系成员基因检测结合颈部超声和降钙素检查有利于甲状腺髓样癌的早期诊断;对于无症状Y 606C 突变携带者,应根据其降钙素水平及颈部超声检查情况实施个体化临床处置。      

C-erbB-2癌基因蛋白、EGFR、TGF-β1在胰腺癌组织中的表达及意义

目的了解C-erbB-2癌基因蛋白、表皮生长因子受体(EGFR)、转化生长因子-β1(TGF-β1)在人胰腺癌中的表达情况,探讨其与胰腺癌进展、转移的关系.方法应用SABC染色法对10例正常胰腺(NP)、13例慢性胰腺炎(CP)和36例胰腺导管腺癌(PC)石蜡组织切片进行C-erbB-2蛋白、EGFR,TGF-β1免疫组化染色.结果C-erbB-2蛋白、EGFR在NP中无表达,仅在一例CP中二者均阳性,在PC中阳性率分别为41.7%,50.0%;明显高于NP组和CP组(均P<0.05);TGF-β1在NP组、CP组、PC组阳性率分别为0.0%,7.7%和44.4%,PC组与前两组比较差异有显著性(P<0.05).三种蛋白单独表达与PC者的年龄、性别和肿瘤大小、部位及组织学分级无关(均P>0.05),与临床分期有关(P<0.01);三种蛋白共同阳性率为27.8%,其共同表达与肿瘤组织学分级、临床分期有关.结论检测C-erbB-2蛋白、EGFR和TGF-β1在胰腺组织标本中的表达,对判断胰腺癌的恶性程度、病程进展及转移趋势有参考价值.     

肺部良、恶性病变中p53蛋白与AgNOR的检测及相关性研究

【目的】为探讨肺部良、恶性病变中ｐ５３蛋白的表达与核仁组成区银染色（ＡｇＮＯＲ）的检测及相关性。【方法】采用链霉素亲生物素－过氧化物酶免疫组化方法和ＡｇＮＯＲ法对４５例肺癌和３０例肺部良性病变进行了检测。【结果】ｐ５３蛋白在肺癌组织中表达总阳性率达８０％,肺部良性病变组织呈阴性。在ｐ５３蛋白阳性肺癌组织中ＡｇＮＯＲ细胞核颗粒均数为（９．６３±０．７０）,而肺部良性病变组织中其颗粒均数（１．９２±０２９）,两组比较差异有显著性（Ｐ＜０．０１）。【结论】ｐ５３蛋白可作为肺癌细胞的肿瘤标志物之一,为肺癌诊断提供参考。ＡｇＮＯＲ定量能区别肺部良、恶性病变,并与ｐ５３蛋白表达呈正相关。     

Analysis of c-kit exon 11 and exon 17 of urticaria pigmentosa that occurred in monozygotic twin sisters

Genomic DNA extracted from peripheral blood mononuclear cells of monozygotic twin patients with urticaria pigmentosa was investigated for mutations of proto-oncogene c-kit. Neither the patients nor their families had genomic mutations in exon 11 or exon 17 of c-kit. The patients did not have any systemic involvement or bone marrow abnormalities. There are indications that some genetic factors may participate in the pathogenesis of urticaria pigmentosa in monozygotic twins. In the present patients, factors other than genomic faults in exon 11 and exon 17 of c-kit may be responsible for the pathogenesis.     

Expression of the RET proto-oncogene in human Embryos

The patterns of RET proto-oncogene expression in mouse, rat, and chicken and the anomalies observed in targeted RET mutants suggest that RET plays a major role in development of mouse enteric nervous system and in kidney organogenesis. Here, we report on in situ hybridization studies describing the pattern of RET proto-oncogene expression during early development of human embryos between 23 and 42 days. We show that the RET gene is expressed in the developing kidney (nephric duct, mesonephric tubules, and ureteric bud), the presumptive enteric neuroblasts of the developing enteric nervous system, cranial ganglia (VII+VIII, IX, and X) and in the presumptive motor neurons of the spinal cord. Yet, despite the high level of RET gene expression in the kidney and in the motor neurons of the developing central nervous system in human embryos, only rare cases with renal agenesis have been reported in Hirschsprung disease patients, and no clinical evidence of spinal cord involvement has been shown in patients carrying RET germline mutations (i.e., multiple endocrine neoplasia syndromes and Hirschsprung disease). Am. J. Med. Genet. 80:481–486, 1998. © 1998 Wiley-Liss, Inc.     

Apoptosis in colorectal carcinoma occurring in patients aged 45 years and under: relationship to prognosis,mitosis, and immunohistochemical demonstration of p53, c-myc and bcl-2 protein products

The aim of this study was to ascertain whether apoptotic counts have prognostic significance in colorectal cancer and if such counts are related to the expression of proteins implicated in cell cycle regulation. Material from a cohort of patients aged 45 years or less with colorectal carcinoma was re-examined to determine apoptotic and mitotic counts by light microscopy, in addition to assessing p53, c-myc, and bcl-2 protein status by immunohistochemistry. The apoptotic index in the 74 patients who were alive or who had died of colorectal carcinoma ranged from 1·2 per cent to 12·3 per cent and exhibited independent prognostic significance, with high counts predicting better survival (P=0·02). Mitotic counts were not related to survival, despite a close correlation with apoptosis (r=0·85). Tumours regarded as not staining with the CM1 antibody for p53 protein demonstrated higher apoptotic counts, compared with those that stained (medians 5·2 and 4·0 per cent, respectively; P=0·03), but p53 expression was found not to be related to survival. The 68 tumours which stained for c-myc appeared to exhibit higher mitotic counts than those that did not. bcl-2 was detected in only four tumours. The latter two proteins exhibited no apparent relationship to the apoptotic index or survival. Although these results indicate a potential role for apoptotic counting in prognostic prediction in colorectal tumours, this is an uncommon group of patients who exhibited some atypical features. The likelihood of a proportion of cases arising within hereditary non-polyposis colorectal cancer syndrome may limit the application of the findings to a more general population with cancer of the colon and rectum. Further work is required, including critical measurement of reproducibility and assessment of the relative impact of this parameter compared with ‘traditional’ prognostic markers. © 1997 John Wiley & Sons, Ltd.     

A novel splice variant of HER2 with increased transformation activity

The HER2 proto-oncogene (also known as neu or c-erbB-2) belongs to the epidermal growth factor receptor family. HER2 is frequently amplified in human carcinomas. Gene amplification or overexpression of HER2 has been correlated with poor prognosis in several human cancers. Point mutation in the rat HER2 homolog, neu, is involved in the formation of rat neuroblastomas. However, no similar mutation in HER2 has been found in human cancers. Here we report the identification of a novel alternative splicing form of HER2 (ΔHER2) in human cell lines. An exon 16 amino acids long in the extracellular domain was deleted in ΔHER2. Deletion mutations in the corresponding region were shown previously to be involved in the formation of mammary carcinomas in transgenic mice. In the focus-formation assay, ΔHER2 showed much stronger transformation activity than did wild-type HER2. This result suggests that the deleted 16–amino acid exon may play a regulatory role in HER2 transformation activity. Mol. Carcinog. 23:62–68, 1998. © 1998 Wiley-Liss, Inc.     

ANALYSIS OF THE RET PROTO-ONCOGENE IN SPORADIC PARATHYROID ADENOMAS

Missense germline mutations of the RET proto-oncogene have recently been identified in the hereditary cancer syndromes MEN2A, MEN2B, and FMTC, all characterized by medullary carcinoma, but also including phaeochromocytoma in MEN2A and MEN2B and parathyroid disease in MEN2A. In addition, somatic RET proto-oncogene mutations have been identified in a subset of sporadic medullary carcinomas and phaeochromocytomas. This study investigated the possibility that RET plays a role in sporadic parathyroid neoplasia. Firstly, normal and neoplastic parathyroid tissues were screened for expression of the RET proto-oncogene, using an RT-PCR approach on autopsy material. Secondly, 20 archival parathyroid adenomas were screened for somatic mutations in the transmembrane region of RET, the region associated with germline mutations in MEN2A and hence parathyroid disease, using a PCR–solid phase direct sequencing approach. RET expression was identified in all the parathyroid tissues analysed. However, no mutations were identified in any of the 20 adenomas, suggesting either that other mechanisms of RET activation occur, such as translocation, or that RET plays a more minor role in the growth control of the parathyroid cells than in C cells or phaeochromocytes.     

Tumor Protein p53 and K-ras Gene Mutations in Peruvian Patients with Gallbladder Cancer

Background: Recent studies have shown that genetic alterations are associated with the effect of patient geographiclocation on gallbladder cancer development. Peru has a high incidence of gallbladder cancer, but causative factorshave not yet been identified. We examined the frequency of mutations in TP53 and K-ras genes in Peruvian patientswith gallbladder cancer, and compared this with data from Bolivia, Hungary, Chile, and Japan, which have a highgallbladder cancer incidence. Methods: DNA was extracted from formalin-fixed paraffin-embedded gallbladder tissuesections of 30 gallbladder cancer patients (9 men and 21 women) obtained using microdissection. Mutations in exons5 to 8 of TP53 and codons 12, 13, and 61 of K-ras were examined using direct sequencing. Results: TP53 mutationswere observed in 10 (33.3%) of patients, but K-ras mutations were absent. Nine (90%) TP53 mutations were pointmutations (7 missense and 2 silent mutations), and the most frequent substitution was a G:C to A:T transition. G:C toA:T transitions at the CpG site or G:C to T:A transversions were found in one patient each. No significant differenceswere found in the frequency of TP53 and K-ras mutations among patients in the 5 countries. Conclusions: Our findingssuggest that endogenous mechanisms and exogenous carcinogens may affect the carcinogenic process in Peruviangallbladder cancer patients, similar to that in Bolivian patients. Further studies with a larger sample size are neededto clarify these findings.