Expression of ras p21 and myc p64 oncoproteins in imprint smears of lung-cancer

The expression of ras p21 and myc p64 was examined in imprint smears of 52 patients with lung cancer and 44 patients with benign disorders, by immunochemistry. Imprint smears were-taken from fresh bronchial biopsies during diagnostic bronchoscopy. Both ras and mye oncoproteins were found to give negative reaction in all benign examined cases; Of the 52 malignant bronchial tissue imprint smears, 28 (54%) and 30 (58%) were positively stained with ms p21 and mye p64 antibodies respectively. Positive staining of ras p21 was demonstrated in 54.5% of squamous cell carcinoma, in 80% of adenocarcinoma and in 0% of small cell carcinoma imprint smears. Positive staining of myc p64 was demonstrated in 45.4% of squamous cell carcinoma, in 50% of adeno-carcinoma and in 100% of small cell carcinoma. The results of this study indicate that both ras and myc oncoproteins detected in bronchial biopsies, may play a crucial role in lung cancer.     

联合检测p53,ras,c—myc癌基因蛋白对恶性胸腔积液诊断价值的研究

目的：为了早期、快速、准确地诊断恶性胸腔积液。方法：用免疫组织化学ＡＢＣ法联合检测了２７例恶性胸腔积液和良性胸腔积液细胞中的ｐ５３、ｒａｓ、ｃ－ｍｙｃ癌基因蛋白的表达水平，恶性胸腔积液同时还与常用的四种诊断方法包括乳酸脱氢酶、癌胚抗原、细胞学、胸膜活检相对照。结果：恶性胸腔积液上述三种癌基因蛋白联合表达的敏感性为８５．３％，特异性为１００％，明显高于常用方法，而良性胸腔积液上述三种癌基因蛋白均为阴性表达。结论：联合检测上述三种癌基因蛋白为诊断恶性胸腔积液提供一条新的可靠途径。     

Oncogene Amplification in Squamous Cell Carcinoma of the Oral Cavity

We have determined the prevalence of amplification of c- myc , N- myc , L- myc , H- ras , Ki- ras , and N- ras oncogenes in 23 cases of squamous cell carcinoma of the oral cavity, using Southern hybridization analysis of DNA extracted from the primary tumor tissues. Nick-translated oncogene probes and oncogene inserts labeled to high specific activities were used. We observed a 5- to 10-fold amplification of one or more of c- myc , N- myc , Ki- ras and N- ras oncogenes in 56% of the tumor tissue samples, with these oncogenes not being amplified in the peripheral blood cells of the same patients, L- myc and H- ras were not amplified in any of our samples. The oncogene amplifications seemed to be associated with advanced stages of squamous cell carcinomas, with the ras and myc family oncogenes being amplified in stages 3 and 4. Hybridization with N- myc detected an additional 2.3 kb Eco RI fragment, along with the normal 2.1 kb fragment. Our data also demonstrated amplification of multiple oncogenes in the same tumor tissue sample. About 60% of the samples with amplified oncogenes showed simultaneous amplification of 2 or more oncogenes. The results showing different oncogene amplifications in similar tumors, as well as multiple oncogene amplifications in the same tumor, suggest that these oncogenes may be alternatively or simultaneously activated in oral carcinogenesis.     

Amplification of protooncogenes in surgical specimens of human lung carcinomas

The possible existence of amplification or rearrangement of protooncogenes was examined in more than 100 surgical specimens of human lung carcinoma. Protooncogenes were amplified in 28% of the carcinomas. About 90% of the amplified genes were of the myc, ras, or erbB family. Of the myc family genes, myc was amplified in 14 of 137 tumors and L-myc in four of 108 tumors, but N-myc was not amplified. A high frequency of amplification of myc was observed in squamous cell carcinomas (seven of 37) and of L-myc in small cell carcinomas (two of six). Of the ras family genes, K-ras-2 was amplified in six of the 137 tumors and N-ras in two of the 137 tumors, but no amplification of H-ras-1 was detected. Seven of the eight cases of amplified ras genes were in advanced pathological stages. Of the erbB family genes, erbB-1 (epidermal growth factor receptor) was amplified in 10 of 114 tumors and erbB-2 (HER-2/neu) in one of 51 tumors. Amplifications of the myc, ras, and erbB family genes might be one of the crucial DNA abnormalities involved in the development of human lung carcinomas.     

Role of oncogenes and tumour suppressor genes in human lung carcinogenesis.

Six families of activated protooncogenes, ras, raf, fur, neu, jun and myc have so far been associated with human lung cancer. Human bronchial epithelial cells in vitro are being used to investigate the functional role of these specific oncogenes and growth regulatory genes in carcinogenesis and tumour progression. When transferred into normal human bronchial epithelial cells by the highly efficient protoplast fusion method, the v-Ha-ras oncogene initiates a cascade of events leading to decreased responsiveness of these cells to inducers of squamous differentiation, aneuploidy and, less frequently, 'immortality' and tumorigenicity with metastasis in athymic nude mice. Transfection of the SV40 T antigen gene results in nontumorigenic cell lines that have a nearly normal pathway of terminal squamous differentiation and can be transformed into malignant cells by transfected Ha-ras, N-ras or Ki-ras. The combination of transfected c-myc and c-raf-1 also transforms human bronchial epithelial cells into neoplastic cells that exhibit some phenotypic traits found in small-cell carcinomas. These and other results indicate that proto-oncogenes dysregulate the pathways of growth and differentiation of human bronchial epithelial cells and play an important role in human carcinogenesis. Analyses of allelic deletion and somatic cell hybrids are being used to identify the chromosomal localization of tumour suppressor genes. We have examined 54 non-small-cell bronchogenic carcinomas with 13 polymorphic markers. Loss of heterozygosity was more frequent than among 23 squamous-cell carcinomas than among 23 adenocarcinomas or eight large-cell carcinomas. Loss of heterozygosity for chromosome 17p was found in 89% of cases of squamous-cell carcinoma and 18% of adenocarcinomas. Analysis of chromosome 11 for allelic deletions revealed two commonly deleted regions (11p13 and 11p15.5). Somatic cell hybrids between normal human bronchial epithelial cells and Hut292DM, a lung carcinoma cell line, had a finite lifespan in vitro and were nontumorigenic in athymic nude mice. Tumour suppressive effects of individual or combinations of specific human chromosomes on Hut292DM are being examined by formation of microcell-cell hybrids. Chromosome 11 has tumour suppressor activity in these hybrids. Both of these studies suggest that tumour suppressor genes play a dominant role in lung carcinogenesis and provide in-vitro model systems for isolating these genes by subtraction library and insertional mutagenesis techniques.     

Expression of ras and myc oncogenes in human hepatocellular carcinoma and non-neoplastic liver tissues

An immunohistochemical assay was used to assess expression of ras p21 and myc p62 oncogene products in human hepatocellular carcinoma (HCC) and non-neoplastic liver tissues. The monoclonal antibodies Y13 259 and Myc1-9E10, specific for ras p21 and myc p62 oncoproteins, were employed on paraffin-embedded sections. Most HCCs showed enhanced ras p21 and myc p62 expression, as indicated by staining intensity. Cirrhotic livers revealed increased myc p62 and occasionally increased ras p21 expression. HBsAg+ hepatocytes showed intense immunostaining for ras p21. Fibrotic, cholestatic, fetal and normal adult liver did not present enhancement of oncoprotein production. We suggest that combined over-expression of ras and myc oncoproteins may be important for the malignant phenotypic alteration in human HCC.     

Evidence for synergistic interactions between ras, myc and a mutant form of p53 in cellular transformation and tumor dissemination.

Mouse 10T1/2 cells were transfected with combinations of T24 H-ras, human c-myc and the proline 193 mutant form of p53. The three-gene ras/myc/p53 combination was significantly more efficient than single genes or double gene combinations in inducing transformed foci in vitro. An analysis of cell lines isolated after transfections with ras, ras/myc, ras/p53 and ras/myc/p53 indicated that the last combination contained significantly higher levels of ras protein than the other combinations, produced tumors in syngeneic mice with a shorter latency period, and exhibited an increased ability to form lung tumors in an in vivo experimental metastasis assay. Synergistic interactions between ras, myc and mutant p53 genes were observed in focus formation and metastasis assays, suggesting that the action of the three oncogenes in malignant transformation occurs along separate but interactive pathways. These results support a working model of oncogene cooperativity in which alterations in myc and p53 permit elevated expression of ras, which is important in a mechanism affecting both cellular transformation in vitro and tumor dissemination in vivo.     

Immunocytochemical study of RAS oncoprotein in cytologic specimens of primary lung tumours

We have examined the distribution of ras p21 oncoprotein expression in cytologic specimens from 73 primary bronchial carcinomas using an immunocytochemical analysis. The cytologic preparations studied represent the two major groups of histological types of lung cancer: Small Cell Lung Carcinoma (SCLC) and Non-Small Cell Lung Carcinoma (NSCLC) (squamous cell carcinoma and adenocarcinoma). The differential expression of ras p21 oncoprotein correlated with histological classification and was found in 30% of 23 small cell lesions, 61% of 28 squamous cell lung carcinomas and 32% of 22 adenocarcinomas. The ras p21 oncoprotein was commonly expressed in NSCLC cases (48%) as compared to SCLC cases (30%).     

联合检测EGFR、CEA对恶性胸腔积液的诊断价值

目的:评价联合检测胸腔积液患者的胸水细胞块表皮生长因子受体（epidermal growth factor receptor,EGFR）基因拷贝数,以及胸水、血清CEA水平对良恶性胸腔积液鉴别诊断的价值。方法:应用荧光原位杂交技术（Fish法）检测恶性胸腔积液（n=35）、良性胸腔积液（n=30)组患者胸水细胞块EGFR基因拷贝数水平。采用电化学发光全自动生化分析仪检测胸水及血清中CEA水平,根据受试者工作特性曲线（ROC）选取最佳灵敏性和特异性的点作为临界值,评价CEA及联合检测EGFR基因拷贝数对良恶性胸腔积液的诊断价值。结果:35例恶性胸腔积液完成Fish检测。恶性胸腔积液中15例阴性,20例阳性,阳性率为57.1％。其中13例为EGFR基因高度多体性,7例为EGFR基因扩增。肺腺癌16例中,EGFR基因高度多体性、扩增14例,肺腺癌扩增率为87.5％;肺鳞癌14例中,EGFR基因簇状扩增3例(21.4％),点状扩增3例(21.4％),无扩增8例(57.1％),肺鳞癌扩增率为42.9％。腺癌Fish阳性率(87.5％)高于鳞癌(42.9％）,P<0．01。30例良性胸腔积液中有1例脓胸患者EGFR Fish检测阳性,阳性率为3.3%,余检测结果均阴性。恶性胸腔积液患者胸水及血清CEA分别为（220.9±71.65）ng/ml、(18.11±11.38）ng/ml,显著高于良性胸腔积液组（2.31±1.29)ng/ml、(1.67±1.06）ng/ml,差异有统计学意义（P<0.01）。其中,恶性胸腔积液胸水CEA明显高于血清CEA,而良性胸腔积液组中,胸水CEA与血清CEA无明显差异。肺腺癌所致胸水及血清CEA分别为（441.02±102.65)ng/ml、(32.87±28.66）ng/ml,鳞癌所致胸水及血清CEA分别为（28.75±21.39）ng/ml、（5.99±5.32）ng/ml,腺癌显著高于鳞癌,差异有统计学意义（P<0.01）。比较胸水EGFR、CEA对良恶性胸腔积液诊断的效能,两者之间无明显差异（P=0.453＞0.05）。Spearman相关性分析胸水EGFR同CEA之间存在显著正相关。结论:EGFR在恶性胸腔积液的形成中起重要作用,通过Fish技术检测胸水细胞块EGFR基因拷贝数可行,其敏感性为57.1%。对肺腺癌导致恶性胸腔积液的诊断敏感性为87.5%。CEA（临界值5.0ng/ml）在恶性胸腔积液及血清中显著高于良性,其中胸水CEA检测诊断敏感性为65.7%,而在腺癌中为87.5%,其在胸水及血清中的比值＞1.5有助于恶性胸腔积液的诊断。EGFR基因突变阳性与肿瘤标记物CEA阳性表达呈正相关,尤见于肺腺癌患者,两者联合检测可提高诊断性试验的准确性。     

P63 differentiates subtypes of nonsmall cell carcinomas of lung in cytologic samples

BACKGROUND:

Bevacizumab in combination with carboplatin and paclitaxel improves overall response and survival in patients with advanced or recurrent nonsmall cell lung carcinoma. However, this drug is not recommended in patients with squamous cell carcinoma or neoplasms with a dominant squamous component. Therefore, identification of squamous cell differentiation has therapeutic implications. In many instances, cytology is the diagnostic tool of choice; however, routine cytomorphology is limited in classification of nonsmall cell carcinomas into squamous and nonsquamous subtypes. The aim of this study was to identify the value of p63 immunocytochemical analysis in this distinction.

METHODS:

Review of cytology records identified 51 consecutive pulmonary specimens (16 fine needle aspiration samples, 15 washes, 12 brushes, and 8 lavages) with the diagnosis of nonsmall cell lung carcinoma (9 carcinomas with squamous differentiation and 42 carcinomas without squamous differentiation). Histologically, they all proved to be nonsmall cell carcinomas, 26 with squamous differentiation and 25 without squamous differentiation. p63 immunocytochemical stain was performed on archival alcohol‐fixed Papanicolaou‐stained cytology slides using standard immunocytochemical methods.

RESULTS:

Twenty‐three (88 %) of the 26 histologically proven squamous cell carcinomas were positive for p63 on cytologic smears. By using p63 immunocytochemistry, the authors detected 14 carcinomas with squamous differentiation not identified by cytomorphology. Smears from all histologically proven carcinomas with squamous differentiation were positive for p63. Sensitivity of cytology for the detection of nonsmall cell carcinoma of lung with squamous differentiation increased from 35% to 88% using p63 immunocytochemistry (P = .001; McNemar test). The squamous component in 4 carcinomas was detected only in cytologic and not in corresponding histologic samples when subsequent p63 immunostaining was performed.

CONCLUSIONS:

The authors concluded that p63 is a useful marker for the detection of nonsmall cell carcinomas of lung with squamous differentiation when used in cytologic pulmonary samples. p63 immunocytochemistry significantly increases the sensitivity for the identification of lung neoplasms with squamous differentiation from 35% to 88% (P = .001). Therefore, p63 immunocytochemistry may be used in pulmonary cytologic samples of nonsmall cell carcinomas to identify squamous differentiation and to improve therapeutic selection of patients with lung cancer. Cancer (Cancer Cytopathol) 2009. © 2009 American Cancer Society.     

Sequential expression of myc-, ras-, oncogene products and EGF receptor during DMBA-induced tongue carcinogenesis

The mechanism leading to development of oral cancer has not been completely understood. It is currently believed that alternation of a number of genes can result in the development of epidermoid carcinomas. In this investigation, we used a 9,10-dimethyl 1,2-benzanthracene (DMBA)-induced carcinogenesis in a hamster tongue model to investigate the expression of c-myc, c-Ha-ms proteins and epidermal growth factor receptor (EGFr). During the DMBA-carcinogenesis of the tongue, the number of c-myc protein positive cells were increased in epithelial dysplasia and elevated throughout the process of tumorigenesis. The expression of c-Ha-ras protein was detected in normal epithelium. The level of c-Ha-ras protein expression was decreased in the dysplastic stage, and it was almost negative in squamous cell carcinomas. Detection of EGFr overexpression occurred only after 1-4 weeks of DMBA treatment, at a very early stage of tumor development, and increased through carcinogenesis varying individually within the malignant tissues. These results suggest that c-myc protein and c-Ha-ras protein expression may have an important role in malignant transformation, and the overexpression of EGFr can be correlated to very early stages of tumor development in the DMBA-induced in vivo tongue carcinogenesis.     

ras, c-myc and c-erbB-2 oncoproteins in human breast cancer

The expression of ras, c-myc and c-erbB-2 oncoproteins in 100 human (73 ductal and 27 lobular) breast carcinomas has been examined using an immunohistochemical analysis. The monoclonal antibody Y13 259 has been used for the ras p21, the monoclonal antibody Myc1-9E10 for the c-myc p62 and the polyclonal antibody pAb1 (from Triton Bioscience Inc.) for the c-erbB-2 p185 oncoproteins. The following conclusions can be drawn from the analysis: Of the 100 breast carcinoma cases studied only 14 did not express any of the three oncogenes. The remaining 86 were positive for one or more of the three oncoproteins. Ductal carcinomas expressed oncoproteins in 92% of the cases (67/73), whereas lobular carcinomas expressed them in 70% of the cases (19/27). The most frequently expressed was c-myc p62 in 70% of cases followed by ras p21, 55% and c-erbB-2, 35%. Elevated expression of ras, myc or erbB-2 oncogenes did not correlate with the presence of metastasis in auxiliary lymph nodes, the numbers of infiltrated lymph nodes the grade of the tumor or hormone status. However, there appears to be a correlation between increased ras staining intensity and patient's age, below 50 years.     

宫颈鳞癌组织HPV16/18 感染与多个癌基因产物表达的研究

 目的　探讨 HPV1 6、1 8的感染及多个癌基因的激活在宫颈鳞癌发生发展中的作用。方法　采用免疫组化方法对 1 9例慢性宫颈炎、40例宫颈上皮内瘤变 ( CIN)及 70例浸润性宫颈鳞癌进行 E6、PCNA、p5 3、p2 1 ras和 c- myc蛋白检测。结果　CIN 和浸润性宫颈鳞癌组 E6、PCNA、p5 3、p2 1 ras阳性率明显高于慢性宫颈炎、CIN 和 CIN ,而其 c- myc阳性率则明显低于其它几组。结论　 HPV1 6、1 8的感染及 PCNA、p5 3、p2 1 ras、c- myc的异常表达与宫颈鳞癌的发生发展密切相关。     

肺鳞癌细胞p~(53)蛋白及ras p~(21)的免疫组织化学定量研究

应用免疫组织化学方法检测２２例肺鳞癌组织标本的ｐ５３及ｒａｓｐ２１表达，用显微图像分析仪测定阳性细胞百分率Ｐ／Ａ（％）和平均光密度（ＡＯＤ），并采用阳性水平指数（ｐｏｓｉｔｉｖｅｌｅｖｅｌｉｎｄｅｘ，ＰＬＩ）作为免疫组化反应水平指标，对癌基因蛋白进行比较研究。结果显示：ｐ５３表达阳性率为５０％，ｒａｓｐ２１表达阳性率为６３６％。ｐ５３蛋白表达在非角化型鳞癌组高于角化型鳞癌组；ｒａｓｐ２１的表达随组织分化程度的增高而增高，ｒａｓｐ２１与ｐ５３的表达水平无直线相关关系。     

Differential expression of p21ras gene products among histological subtypes of fresh primary human lung tumors

Activation of the ras oncogene has been associated with a number of human tumors. In this study, expression of p21ras in different histological types of fresh primary bronchogenic carcinomas was examined. p21ras products were detected in all lung tissues that were analyzed. Only 1 of 23 tumors demonstrated aberrant migration of p21ras. In contrast, 10 tumors had substantially elevated levels of p21ras products with respect to the adjacent normal lung tissues and with respect to the other lung tumors. There was no correlation between increased ras protein expression and tobacco exposure of the patient or extent of disease at the time of diagnosis. However, 9 of 11 tumors with a squamous component as opposed to only 1 of 12 tumors belonging to other histological classifications demonstrated increased p21ras. These data suggest that, in bronchogenic carcinomas, mutations associated with structural abnormalities and aberrant migration of p21ras occur infrequently as compared to quantitative changes in p21ras. Furthermore, differential expression of c-ras products in primary human lung tumors correlates with pathological cell type, and may be a common event in squamous cell carcinomas, but not adenocarcinomas or small cell carcinomas of the lung.     

免疫标志物及AB／PAS黏液染色在子宫颈癌分型中的应用研究

目的：探讨免疫标志物细胞角蛋白7（cytokeratin 7,CK7）、低分子质量细胞角蛋白CAM5．2、癌胚抗原（carcino-embryonic antigen,CEA）、癌基因p63、高分子质量细胞角蛋白34βE12及阿利新蓝-过碘酸雪夫氏（alcian blue-periodic acid schiff,AB／PAS）黏液染色在子宫颈癌分型中的意义。方法采用免疫组织化学EnVision法检测CK7、CAM5．2、CEA、p63、34βE12在59例子宫颈癌中的表达,结合AB／PAS黏液染色,分析上述免疫标志物及特殊染色与子宫颈癌分型的关系。结果 CK7、CAM5．2、CEA在子宫颈腺癌（6例）、腺鳞癌（4例）的腺癌细胞质中均有100．0％的表达,低分化鳞癌（34例）中CK7、CAM5．2阳性率分别为52．9％、32．4％,而中及高分化鳞癌（15例）中不表达。CEA在鳞癌中有不同程度表达,中及高分化鳞癌仅在角化区域表达,低分化鳞癌中阳性率44．1％;p63在腺癌中不表达,在鳞癌中100．0％表达;34βE12在腺癌及鳞癌中均有100．0％表达,鳞癌中强度高,腺癌中较弱;AB／PAS在子宫颈腺癌、腺鳞癌、低分化鳞癌中发生率分别为83．3％（5／6）、75．0％（3／4）、5．9％（2／34）,但表达程度很弱。结论 CK7、CAM5．2、p63、34βE12联合检测对子宫颈癌的分型有重要意义。AB／PAS黏液染色对子宫颈癌有一定的鉴别作用。     

Diagnostic approach of effusion cytology using computerized image analysis

The objective of this study is to investigate whether image cytometry is a sensitive and specific method for the differential diagnosis of equivocal cells in routine cytology of effusion smears. One hundred four effusion smears were studied from routine cytologic material. Cytologically 56 (53.8%) of the smears were classified as malignant, 26 (24%) as suspicious and 22 (21.1%) as benign. Two morphometric variables (nuclear major axis length and nuclear area) of the nuclei were measured by an image analysis system. Higher values for the area were found for malignant rather than benign and suspicious cells (p < 0.0005 and p < 0.005 respectively). The same result was extracted for the nuclear major axis length values (p < 0.0005 and p < 0.0005 respectively). Values of nuclear major axis length and nuclear area didn't differ significantly between benign and suspicious cells (p = 0.071 and p = 0.066 respectively). The results show that the range of the values for suspicious cells is closer to the range of the benign cells. Cytomorphometry of the effusion smear cells may provide important information for the differentiation of atypical mesothelial cells from malignant adenocarcinoma cells.     

The influence of epidermal growth factor receptor and tumor differentiation on the response to accelerated radiotherapy of squamous cell carcinomas of the head and neck in the randomized DAHANCA 6 and 7 study.

BACKGROUND AND PURPOSE: Reduction of the overall treatment time of radiotherapy has increased locoregional control and disease specific survival in squamous cell carcinomas of the head and neck (HNSCC), but the response is heterogeneous. EGFr is often overexpressed in HNSCC and has been related to the repopulation taking place during radiotherapy. The aim of the current study was to address the influence of EGFr and histopathological differentiation when the overall treatment time of radiotherapy was moderately reduced. PATIENTS AND METHODS: Eight hundred and three patients with representative pretreatment tissue samples from the randomized DAHANCA 6 and 7 study of 5 vs. 6 fx/wk of radiotherapy. EGFr was visualized using immunohistochemistry and separated into high and low expression before correlation with clinical data. RESULTS: Tumors with high EGFr (84%) responded better to moderately accelerated radiotherapy, than carcinomas with low EGFr, using locoregional control as endpoint and a similar pattern was seen, stratifying by well/moderate vs. poor tumor differentiation. Therefore, a combined parameter was constructed showing a more prominent separation of response: tumors with high EGFr and well/moderate differentiation did benefit from moderate acceleration of treatment regarding locoregional control, HR 0.54 (0.37-0.78), whereas such an effect was not seen in tumors with low EGFr and/or poor differentiation, HR 0.8 (0.51-1.25). These results reflected the disease specific survival as well and were confirmed in multivariable analyses. CONCLUSIONS: Moderately accelerated fractionation is superior to conventional treatment in HNSCC but the response is heterogeneous and may be predicted by high expression of EGFr and well/moderate tumor differentiation.     

ras oncogene p21 as a tumor marker in the cytodiagnosis of gastric and colonic carcinomas

This study was undertaken to determine whether the expression of ras oncogene product p21 can be used as a tumor cell marker of gastric and colonic carcinoma in brush smears. To detect p21 an immunocytochemical assay with RAP-5 monoclonal antibody was used. Benign epithelial gastric cells obtained from normal gastric mucosa or benign gastric lesions reacted negatively in 12 out of 13 cases. Similarly, benign epithelial colonic cells from normal colon or benign colonic lesions were negative for p21 in nine out of ten cases. Weakly positive reaction, confined to a few cell clusters only, was observed in one smear of a benign gastric ulcer and one smear of chronic ulcerative colitis. All 20 smears from colonic carcinoma and all 20 smears of gastric carcinoma contained cells that stained positively for p21, and the degree of tumor differentiation had no impact on the staining pattern. The results recorded in this study show that the immunocytochemical assay for the ras oncogene product may prove to represent a new tool for the cytodiagnosis of gastric and colonic carcinomas.     

Immunohistochemical demonstration of ras p21 oncogene product in normal, benign, and malignant human thyroid tissues

The p21 protein product of the cellular oncogene ras, designated ras p21, has been detected immunohistochemically in normal, benign and malignant human thyroid tissues. With the monoclonal antibody RAP-5 generated against a synthetic peptide corresponding to amino acid positions 10 to 17 of the ras p21 protein and an avidin-biotin-peroxidase complex (ABC), the expression of the ras p21 was evaluated in paraffin-embedded sections. Western blot analysis using fresh thyroid carcinoma tissue revealed double protein bands, one band was at molecular weight 21,000 and the other was a more rapidly migrating band at the molecular weight 17,500. Immunohistochemically, papillary adenocarcinomas of the thyroid showed moderate to intense stainings for ras p21 in most cases. Cytoplasmic and apical surface stainings were the most common patterns of immunoreactivity. Adenomas showed variable ras p21 positivity in cytoplasm and apical surface stainings of adenomas were negative to borderline in most cases. The cytoplasm of tissues of Hashimoto's thyroiditis, Graves' disease, and normal thyroid tissues was uniformly ras p21 positive, but the apical cell surface was nonreactive for ras p21 in all tissues. Judging from the findings obtained on this large series of normal, benign, and malignant thyroid tissues, the elevation of ras p21 may be a common event in thyroid neoplasm, and especially elevated ras expression in the apical cell surface may be characteristic to papillary carcinomas of the thyroid. This suggests that apical surface expression of ras p21 may be important in the development of thyroid carcinomas and be useful in differentiation of papillary adenocarcinoma.