大肠肿瘤中bcl—2及PCNA表达及其意义

目的：研究ｂｃｌ－２及ＰＣＮＡ在大肠肿瘤肆生中的作用及其临床意义。方法：应用免疫组化Ｓ－Ｐ法分别检测大肠正常粘膜、腺瘤及腺癌中ｂｃ；－２及ＰＣＮＡ表达。结果：Ｂｃｌ－２在正常粘膜基底部上皮细胞表达，在腺瘤（７７．５％）和腺癌中（５６．３％）ｂｃｌ－２表达差异显（Ｐ〈０．０５）。高分化腺癌ｂｃｌ－２表达率（６８．４％）显高于差分化腺癌（４１．７％），ＰＣＮＡ表达在正常粘膜，腺瘤及腺癌中依次递增，     

Loss of p57KIP2 is associated with colorectal carcinogenesis

The expression and significance of p57KIP2, an important inhibitor of the cell cycle, remain unclear during carcinogenesis and during late metastasis to lymph nodes of tumors. To detail changes of p57KIP2 during colorectal carcinogenesis and during late metastasis to lymph nodes, p57KIP2, cyclin A, cyclin B1, cyclin E, CDK2, and Ki67 were immunohistochemically investigated in 22 specimens of normal mucosa, 62 of adenomas, 17 of carcinomas in adenomas, 189 of primary carcinomas, and 23 of lymph node metastases. Situated in nuclei, p57KIP2 expression increased significantly from normal mucosa to adenomas (p=0.0068), from mild through moderate to severe dysplasia in adenomas (p=0.0132). It significantly decreased from adenomas to unpaired primary carcinomas (p=0.0112) and from peripheral adenomas to paired central carcinomas (p=0.0018), but remained unchanged when primary carcinomas metastasized to lymph nodes (p=0.3401). p57KIP2 expression was not correlated with clinicopathological indices, but the patients having tumors without p57KIP2 tended to show a poor prognosis (p=0.0674). High p57KIP2 was significantly correlated with increased cyclin A (p=0.0007), elevated cyclin B1 (p=0.0007), reduced CDK2 (p=0.0021), and increased Ki67 (p=0.0013) in adenomas. Thus, loss of p57KIP2 expression appears associated with colorectal carcinogenesis.     

Expression of p53, p21/waf, bcl-2, bax, Rb and Ki67 proteins in colorectal adenocarcinomas

This study investigated the combined immunoexpression of p53, p21, bcl-2, bax, Rb and Ki67 proteins in colorectal adenocarcinomas and correlated expression patterns with tumour stage and grade. Paraffin sections from 98 cases of colorectal adenocarcinomas were stained by immunohistochemistry for p53, p21, bcl-2, bax, Rb and MIB-1 (Ki67) proteins. In addition, 12 cases of colorectal adenomas and normal colorectal mucosa were studied in parallel. P53, p21, bcl-2, bax, Rb and Ki67 proteins were detected in at least 5% of tumour cells in 63/98, 72/98, 52/98, 96/98 and 98/98 adenocarcinomas, respectively. Comparative study of the normal-adenoma-carcinoma tissues revealed abrogation of the normal immunotopography in adenomas and adenocarcinomas, and considerable modifications, increase or reduction, of the expression of p53, p21, bcl-2, bax, Rb and Ki67 proteins in adenocarcinomas when compared with normal mucosa and adenomas. Statistically significant correlations were found between low bax expression and Dukes C stage of carcinomas, Ki67 expression and carcinoma grade, and Ki67 and Rb expression. P53, p21, bcl-2 and Rb immunoexpression did not correlate with tumour stage or grade. Our findings show that low bax immunoexpression is frequently related to colorectal adenocarcinomas with lymph node metastases suggesting that low levels of bax expression play a role in late stage colorectal cancer. The correlation between Ki67 and Rb expression, in view of previous data that the hyperphosphorylated inactive Rb protein is frequently increased in colorectal adenocarcinomas, suggests that Rb protein is somewhat ineffective in inhibiting the cell-cycle progression in these malignancies. Furthermore, our findings provide immunohistochemical evidence that the abrogation of the normal immunotopography and the modifications of the expression of p53, p21, bcl-2, bax, Rb and Ki67 proteins reflect important events in colorectal oncogenesis.     

Cyclin B1, unlike cyclin G1, increases significantly during colorectal carcinogenesis and during later metastasis to lymph nodes

In collaboration with p53, cyclins B1 and G1 regulate the G2/M transition, a key checkpoint in the active cell cycle, which can be monitored by Ki67. However, the cyclin B1 expression remains unclear during colorectal carcinogenesis and during later metastasis to lymph nodes, and cyclin G1 expression is not clear in colorectal tumors. To clarify the variations of the two cyclins in colorectal tumors, cyclin B1, cyclin G1, p53, and Ki67 were immunohistochemically stained in 22 normal mucosa, 62 adenomas, 17 carcinomas in adenomas, 194 primary carcinomas, and 21 lymph node metastases; and the two cyclins were examined by Western blot in other 10 pairs of normal mucosa and primary carcinomas. Located in cytoplasms, nuclei or both, cyclin B1 expression increased significantly from normal mucosa through adenomas to primary carcinomas, from adenomas with mild dysplasia through those with moderate to those with severe, from peripheral adenomas to their central carcinomas, and from primary to metastatic foci. These increased expressions were confirmed by Western blot. Cyclin B1 expression, however, declined significantly in primary carcinomas showing large size, mucinous type, deep invasion, or short postoperative-patient-survival time. High cyclin B1 was linked to high p53 in adenomas, and to high Ki67 in adenomas and primary carcinomas. In contrast, found limited to nuclei, cyclin G1 expression did not vary significantly from normal mucosa through to metastatic carcinomas, and was not associated with clinicopathological parameters, p53 or Ki67. The unchanged expressions were confirmed by Western blot. Thus, increased cyclin B1, but not cyclin G1, may promote colorectal carcinogenesis and later metastasis to lymph nodes.     

COX-2 is expressed in human pulmonary, colonic, and mammary tumors

BACKGROUND: The cyclooxygenase (COX) enzyme catalyzes the formation of prostaglandins, which can affect cell proliferation and alter the response of the immune system to malignant cells. The inducible form of COX, COX-2, has been shown to be important in carcinogenesis. METHODS: The authors studied COX-1 and -2 expression in 20 tumors of the lung, colon, and breast (60 total) by using commercially available monoclonal and polyclonal antibodies on formalin fixed, paraffin embedded tissue. Our evaluation also included seven carcinoma-associated colonic adenomas and 10 mammary ductal carcinomas in situ (DCIS). Quantitation of immunoreactivity was accomplished using an immunohistochemical scoring system that approximates the use of image analysis-based systems. RESULTS: Ninety percent of lung tumors (squamous cell carcinomas and adenocarcinomas), 71% of colon adenocarcinomas and 56% of breast tumors (DCIS and infiltrating ductal and lobular carcinomas) expressed COX-2 at a moderate to strong level, which was significantly different from the negligible expression in distant nonneoplastic epithelium (controls; P < 0.0001). Poorly differentiated histologic features were correlated with low COX-2 expression overall, especially in colon carcinomas. Among breast carcinomas, DCIS was more likely to express COX-2 than invasive carcinomas. Adenomatous colonic epithelium showed moderate COX-2 expression, as did adjacent nonneoplastic epithelium. COX-1 immunoreactivity was essentially weak to moderate in all tissues evaluated. CONCLUSIONS: COX-2 expression is upregulated in well and moderately differentiated carcinomas of the lung, colon, and breast whereas COX-1 appears to be constitutively expressed at low levels. A possible COX-2 paracrine effect is suggested by moderate immunoreactivity in adjacent nonneoplastic epithelium.     

Evidence of reciprocity of bcl-2 and p53 expression in human colorectal adenomas and carcinomas.

Evidence of accumulating for the failure of apoptosis as an important factor in the evolution of colorectal cancer and its poor response to adjuvant therapy. The proto-oncogene bcl-2 suppresses apoptosis. Its expression could provide an important survival advantage permitting the development of colorectal cancer. The expression of bcl-2 and p53 was determined by immunohistochemistry in 47 samples of histologically normal colonic mucosa, 19 adenomas and 53 adenocarcinomas. Expression of bcl-2 in colonic crypts > 5 cm from the tumours was confined to crypt bases but was more extensive and intense in normal crypts < 5 mm from cancers. A higher proportion of adenomas (63.2%) than carcinomas (36.5%) expressed bcl-2 (P < 0.05). A lower proportion of adenomas (31.6%) than carcinomas (62.3%) expressed p53 (P < 0.02). A total of 26.3% of adenomas and 22% of carcinomas expressed both bcl-2 and p53. To determine whether these samples contained cells which expressed both proteins, a dual staining technique for bcl-2 and p53 was used. Only 1/19 adenomas and 2/53 carcinomas contained cells immunopositive for both bcl-2 and p53. Moreover there was evidence of reciprocity of expression of bcl-2 and p53 in these three double staining neoplasms. We suggest that bcl-2 provides a survival advantage in the proliferative compartment of normal crypts and colorectal neoplasms. However, its expression is lost during the evolution from adenoma to carcinoma, whereas p53 expression is increased, an event generally coincident with the expression of stabilised p53, which we presume to represent the mutant form.     

High expression of cyclooxygenase-2 in macrophages of human colonic adenoma.

Cyclooxygenase (COX)-2 is a possible molecular target for suppression of colon carcinogenesis by non-steroidal anti-inflammatory drugs (NSAIDs). However, the expression of COX-2 in human colonic tumors during the adenoma-carcinoma sequence has not been elucidated. In the present study, we examined immuno-histochemically the expression and localization of the COX-2 protein in human colonic adenomas and cancers. Twelve human colonic adenomas and 9 advanced cancers were studied. Immunoreactive COX-2 was predominantly and strongly expressed in sub-epithelial interstitial cells broadly present in the surface area of adenomas. The staining pattern of macrophages was similar to that observed for COX-2 in adenomas. Adjacent normal colonic mucosa was negative for COX-2 expression. In contrast, COX-2 was relatively weakly expressed in both tumor cells and interstitial cells in advanced colon cancers. In conclusion, the target of NSAIDs in preventing colon carcinogenesis may be the COX-2 expressed in interstitial cells, possibly macrophages, of colonic adenomas.     

p107 Expression in colorectal tumours rises during carcinogenesis and falls during invasion

p107 Links to cyclin A/CDK2 (cyclin-dependent kinase 2) and cyclin E/CDK2 that are important cell cycle regulators. However, p107 expression remains unclear in almost all kinds of human solid tumours. To clarify the expression of p107 in colorectal tumours, 22 normal mucosae, 9 hyperplastic polyps, 60 adenomas, 198 primary carcinomas, 21 lymph-nodal metastases, and 10 hepatic metastases were immunohistochemically stained for p107, cyclin A, cyclin E, CDK2 and Ki67. Results were measured using labelling indices (LIs). p107 LIs surpassed the highest value in normal tissues in six of nine hyperplastic polyps, 54 of 60 adenomas, 144 of 198 primary cancers, 13 of 21 nodal foci and three of 10 hepatic foci. p107 LIs also apparently rose from normal through hyperplasia and adenoma to early carcinoma. However, they declined in liver-metastatic foci, and in primary cancers showing large size, mucinous type, venous invasion, lymphatic invasion, poorly differentiated type, deep invasion, lymph-nodal metastasis, hepatic metastasis or advanced stage. Low p107 LIs were also linked to a poor survival, particularly in stage-III patients. As the p107 LI gradually rose, the CDK2 (in primary cancers only), cyclin A, cyclin E and Ki67 LIs were elevated concurrently-in both adenomas and primary cancers. Thus, in colorectal tumours, p107 expression rises abnormally and gradually during carcinogenesis and then falls during invasion, and thereby probably perturbs the cell-cycle control and promotes carcinogenesis and invasion. Clinically, reduced p107 may indicate a poorer prognosis.     

Expression of p53, Ki-67 and Bcl-2 in parathyroid adenoma and residual normal tissue

The aim of this study was to investigate the expression of Ki-67, bcl-2 and p53 in parathyroid adenomas and their residual rim of normal parathyroid tissue. Specimens from 26 parathyroid adenomas were studied by immunohistochemical analysis for Ki-67, bcl-2 and p53 expression. Positive findings were noted for p53 in 4 (15%) adenomas and none of the residual rims of normal parathyroid tissue (p = 0.055); for Ki-67 in 15 (56%) adenomas and none of the residual rims of normal parathyroid tissue (p = 0.00002); and for bcl-2 in 19 (73%) adenomas and 8 (31%) residual rims of normal parathyroid tissue (p < 0.01). The high rate of Ki-67 expression may indicate susceptibility of parathyroid adenomas to clonal proliferation. The weak immunoreactive expression of p53, combined with a relatively strong expression of bcl-2, may contribute to the characteristic slow progression of these tumors.     

Altered bcl-2 family expression during non-genotoxic hepatocarcinogenesis in mice.

Dysregulation of apoptosis is an important component of multistage hepatocarcinogenesis. Members of the bcl-2 protein family are important in the regulation of apoptosis and their expression is altered in several cancers. The objectives of the present study were to determine whether the expression of members of the bcl-2 protein family are altered in mouse liver during acute treatment with non-genotoxic carcinogens and throughout non-genotoxic hepatocarcinogenesis. Acute treatment of B6C3F1 mice with phenobarbital resulted in increased levels of bcl-2 and decreased levels of bax protein, while acute treatment with WY-14,643 resulted in increased bcl-2 and BAG-1 protein in the liver. Following chronic treatment, altered hepatic foci and adenomas were classified as: small-cell, heterogeneous basophilic lesions (spontaneous or tetrachlorodibenzo-p-dioxin-induced); large-cell, homogeneous basophilic lesions (WY-14,643-induced); acidophilic lesions (phenobarbital- or chlordane-induced). Of the small-cell heterogeneous basophilic lesions, 86% of foci (31/36) and 85% of adenomas (35/41) exhibited increased bcl-2 protein levels compared with surrounding normal hepatocytes, whereas only 12.5% of foci (4/36) and 12% of adenomas (5/41) exhibited increased bcl-X(L) levels. Of the large-cell, homogenous, basophilic lesions, 100% of foci (3/3) and 90% of adenomas (9/10) expressed bcl-2 protein, whereas 100% of foci (3/3) and 80% of adenomas (8/10) exhibited increased bcl-X(L) protein levels compared with surrounding normal hepatocytes. Of the acidophilic lesions, the majority of foci (28/32, 88%) and adenomas (47/50, 94%) expressed increased bcl-X(L), whereas increased bcl-2 was observed in only 12.5% of acidophilic preneoplastic foci (4/32) and 14% of acidophilic adenomas (7/50). Of the carcinomas analyzed, 81% expressed increased bcl-2 (54/67), 78% expressed increased bcl-X(L) (52/67) and 69% expressed increased levels of both bcl-2 and bcl-X(L) (46/67). Collectively, only 8% of preneoplastic foci, 3% of adenomas and 1.5% of carcinomas did not express either bcl-2 or bcl-X(L). These results suggest that regulation of apoptotic proteins is altered during non-genotoxic carcinogenesis in mouse liver. Furthermore, there were both chemical- and lesion-specific aspects of expression of apoptotic proteins during hepatocarcinogenesis in mice.     

Correlation of Skp2 with carcinogenesis, invasion, metastasis, and prognosis in colorectal tumors

In colorectal tumors, S-phase kinase-associated protein 2 (Skp2) still has numerous important questions unanswered: its expression in adenomas, its correlation with key clinicopathological indices, its association with patient prognosis, its variation in lymph node metastases, and its association with many cell-cycle regulators. To answer these questions in colorectal tumors, Skp2, cyclin A, cyclin B1, cyclin E, CDK2, and Ki67 were immunohistochemically stained in 12 normal mucosa, 36 adenomas, 11 carcinomas in adenomas, 102 primary carcinomas, and 12 paired lymph node metastases; and Skp2 was examined by Western blot in 8 pairs of normal mucosa and carcinomas. Situated in nuclei, Skp2 expression significantly increased from normal mucosa through adenoma to primary carcinoma (p<0.0001), from mild through moderate to severe dysplasia in adenomas (p=0.038), from peripheral adenoma to paired central carcinoma (p=0.0033), and from primary carcinoma to lymph node metastasis (p=0.015), and these increases were confirmed by Western blot. Expression, however, relatively declined significantly in the primary carcinomas showing deep invasion (p=0.0113), lymph nodal metastases (p=0.0268), and poor prognosis for all (p=0.0104) or stage III patients (p=0.0119). High Skp2 was also significantly linked with elevated cyclin A, cyclin B1, cyclin E, CDK2 (in primary carcinomas only), and Ki67 in both adenomas and primary carcinomas. Thus, overexpression of Skp2 is associated with colorectal carcinogenesis and late metastasis to lymph nodes, whereas relative reduction of Skp2 is correlated with local invasion of primary carcinoma.     

Prognostic value of Ki 67/MIB1 automated and quantitative immunolabelling in primary operable breast carcinomas

The prognostic significance of Ki 67/MIB1 immunohistochemical assays (ICAs) was investigated in optimal technical conditions in 139 breast carcinomas. Automated ICAs (immunoperoxidase/Ventana device) was performed on frozen sections. Immunoprecipitates were quantified by computerized analysis (SAMBA) of digitized microscopic images. Mean positive surfaces (%) and quantitative immunocytochemical (QIC) index were correlated to the patients survival (8-year survival). The results showed that Ki 67/MIB1 large surfaces (cutpoint, 20%) and high QIC index (cutpoint, 12) correlated with poor overall survival (Kaplan Meier, log rank test, p=0.011 and p=0.037, BMDP software). In node positive, but not in node negative patients, large Ki 67/MIB1 surface (cutpoint, 20%) and high QIC index (cut-off 12) correlated with the overall patient survival (p=0.0037 and p=0.049). Also large Ki 67/MIB1 positive surface (cut-off, 20%) correlated with disease-free survival in all patients and node positive patients (p=0.022 and p=0.0057) but not in node negative patients. It is concluded that in optimal technical conditions (automated and quantitative immunohistochemical assays on frozen sections) Ki 67 antigen immunohistochemical expression in breast carcinomas tissue has a prognostic significance in node positive patients but not in node negative patients.     

Geminin, Ki67, and minichromosome maintenance 2 in gastric hyperplastic polyps, adenomas, and intestinal-type carcinomas: pathobiological significance

Background

Geminin negatively regulates Cdt1 and induces the formation of prereplicative complexes by loading mini-chromosome maintenance proteins (Mcm) onto chromatin and limiting DNA replication to once per cell cycle. Recent studies have suggested that geminin expression is a marker of the S/G2/M phase of the cell cycle and is associated with a poor prognosis in various human malignancies. This study aimed to clarify the pathobiological role of geminin in intestinal-type gastric carcinoma, and its relationships with minichromosome maintenance 2 (Mcm2) and Ki67 expression.

Methods

We performed western blot analysis of seven human gastric cancer cell lines, and immunohistochemical analysis of 72 gastric mucosal lesions and 128 surgically removed advanced intestinal-type gastric carcinomas. Double-labeling immuno-fluorescence was performed to identify the coexpression of geminin and Ki67.

Results

Geminin was detected in all cell lines. Geminin labeling indices (LIs) in hyperplastic polyps, low-grade adenomas, high-grade adenomas, and intestinal-type adenocarcinomas were 3.9%, 10.5%, 18.6%, and 27.2%, respectively. The equivalent LIs for Ki67 and Mcm2 were 17.7%, 42.2%, 52.6%, and 59.7%; and 26.7%, 70.0%, 67.8%, and 77.8%, respectively. Double-labeling immunofluorescence revealed coexpression of geminin and Ki67 in both normal and tumor cells. The LI for geminin was significantly correlated with N stage, International Union Against Cancer (UICC) stage, Mcm2 LI, and Ki67 LI. Patients in stages I-IV and stage III with higher LIs for geminin (>25%) had significantly worse prognoses (P < 0.05 and P < 0.04, respectively). Univariate Cox regression analysis indicated that the overall survival of stage I-IV tumors was significantly correlated with high geminin LIs (relative risk [RR] = 1.94; P = 0.04).

Conclusions

Geminin expression might reflect the biological nature of gastric intramucosal neoplasms and could be a possible prognostic marker in advanced intestinal-type gastric carcinomas.     

Patterns of proliferative changes in crypts bordering colonic tumors: Zonal histology and cell cycle marker expression

Proliferative crypt changes have been noted in mucosa bordering colonic carcinomas, but their biological significance is disputed. We anticipated that zonal patterning of histological changes and cell cycle marker expression would provide clues to the pathogenesis of these border changes. 81 specimens were examined including carcinomas, adenomatours polyps, adenomas with early carcinoma, flat adenomas and aberrant crypt foci. The spatial distribution and frequency of micro-architectural features, and mucosal thickness were determined in a border domain of 150 300 sequential crypts/specimen. Immunocytochemical expression of Ki67 and p53 antigens in crypts also was semi-quantitatively examined. We found that in 100% of carcinomas two histologically abnormal zones (Proximate and Middle) separated tumor from normal mucosa. Differences in the feature frequency between zones were statistically significant (p<0.05). Both zones showed mild increases in crypt cell expression of Ki67, with a statistically significant relationship to zonal patterning (p<0.005). Weak expression of p53 only appeared in rare cells. Crypt elongation with mucosal thickening (1.9x normal, p<0.001) in the Proximate and Middle zones distinguished carcinomas from border changes in all benign lesions, except flat adenomas. Since this change occurs in all cases of carcinoma, there is no correlation with tumor stage or grade. Also in carcinomas, elaborate complexes of attached crypts (connected crypt structures) were characteristic of the Middle zone, so that proximate zone was always architecturally simpler. We conclude, that despite continuous carcinoma growth, the invaded border mucosa maintains a prototypical zonal organization of molecular and histological crypt changes This spatially organized reaction pattern is likely to reflect an interplay between regulated growth and destructive processes in response to advancing carcinoma. Compared to the edges of benign colonic tumors, the edges of carcinomas are distinctive and consistent enough to be diagnostically useful.     

Expression of beta-catenin and full-length APC protein in normal and neoplastic colonic tissues

Mutations of the APC gene are thought to be early events in the process of colorectal carcinogenesis. Although the complete function(s) of the APC gene product is not known, it has been shown that the APC protein interacts with beta-catenin in a multi-protein complex to regulate the level of expression of beta-catenin. Loss of normal APC protein function can lead to an accumulation of beta-catenin in the cytosol and the nucleus. Immunohistochemical methods were used to determine the relationship between APC and beta-catenin protein expression in human colonic tissues (150 normal, 9 hyperplastic, 58 adenomas and 83 carcinomas) and 12 paired samples of normal and cancer tissue in mouse colon. In all samples of normal human and mouse colonic mucosa and in human hyperplastic polyps both APC and beta-catenin immunoreactivity were present in colonocytes. APC expression was cytoplasmic, with maximal immunoreactivity in the goblet cells. beta-Catenin expression was predominantly localized to the plasma membrane, with no nuclear immunoreactivity. APC immunoreactivity was absent in all of the mouse adenocarcinomas and 83% of the human colon cancers. All of the human and mouse carcinomas had nuclear and cytoplasmic beta-catenin expression. In contrast, only 29% of the 58 colonic adenomas were completely negative for APC immunoreactivity. Regardless of the presence or absence of APC, all of the adenomas had cytoplasmic and nuclear beta-catenin immunoreactivity. Many colonic adenomas retain expression of full-length APC protein whereas it is usually lost in colorectal cancers. Regardless of the status of APC protein expression, beta-catenin protein was found in the cytoplasm and nucleus of all neoplastic colonic mucosa. The dissociation between loss of expression of APC and accumulation of beta-catenin in the nucleus suggests that inactivation of both alleles of the APC gene may not be required for beta-catenin nuclear accumulation in colonic adenomas.     

Expression of survivin correlates with apoptosis, proliferation, and angiogenesis during human colorectal tumorigenesis

BACKGROUND: To identify the role of survivin, a novel inhibitor of apoptosis (IAP) in colorectal tumorigenesis, the authors investigated tissue expression of survivin in human colorectal tumors including 43 hyperplastic polyps, 171 adenomas with low dysplasia, 42 adenomas with high dysplasia, and 60 carcinomas in adenoma, and examined whether the expression of survivin correlated with tumor cell apoptosis, proliferation, and angiogenesis, which is known to initiate the imbalance between cell proliferation and apoptosis. METHODS: Immunohistochemical staining for the paraffin sections by using the monoclonal antibodies, survivin, p53, bcl-2, Ki-67, and CD34, was performed by the standard avidin-biotin-peroxidase technique. The apoptotic cells were detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling method, using an Apop Tag in situ detection kit. RESULTS: The immunoreactivity of survivin significantly increased in the transition from adenoma with low dysplasia to high dysplasia/carcinoma (P < 0.001). Similar changes in protein expression were observed for p53 but not for bcl-2, which was expressed throughout the colorectal tumorigenesis. This transition was associated with a significant decrease in the apoptotic index (AI) and significant increases in the Ki-67 labeling index (LI) and microvessel density (MVD; P < 0.001 for both). The expression of survivin inversely correlated with AI and was positively correlated with Ki-67 LI and MVD (P < 0.001 for both). CONCLUSIONS: These results suggest that, like p53, survivin plays an important role in transition from adenoma with low dysplasia to high dysplasia during human colorectal tumorigenesis.     

Subepithelial myofibroblasts express cyclooxygenase-2 in colorectal tubular adenomas.

PURPOSE: Recent data support the hypothesis that the inducible isoform of cyclooxygenase (COX-2) plays a role in the early stages of colonic carcinogenesis and that nonsteroidal anti-inflammatory drugs (NSAIDs) retard the development of colon cancer by modulating COX-2. However, the cell types responsible for producing COX-2 in colorectal adenomas remain a subject of controversy. EXPERIMENTAL DESIGN: COX-2 expression in normal colonic mucosa (n = 50), hyperplastic polyps (n = 43), sporadic adenomas (n = 67), and invasive colonic adenocarcinoma (n = 39) was studied in formalin-fixed and paraffin-embedded tissue sections from endoscopy biopsy and colonic resection specimens. Immunohistochemistry (avidin-biotin complex technique with double immunolabeling) was used to identify the phenotypes of COX-2-producing cells. RESULTS: In colorectal adenomas, increased expression of COX-2 was detected and localized to alpha smooth muscle actin ( proportional, variant SMA)-positive subepithelial stromal cells (myofibroblasts) in the periluminal region of the lamina propria in 63 (94%) of 67 cases. In contrast, in normal colonic mucosa and in hyperplastic polyps with intact epithelium, COX-2 expression was found only in macrophages and endothelial cells. In areas in which the surface epithelium was ulcerated in normal mucosa as well as hyperplastic or neoplastic polyps, COX-2 expression was increased in granulation tissue (and present in macrophages, endothelium, and myofibroblasts). In invasive carcinoma, COX-2 expression in myofibroblasts was limited to the adenomatous portion of the tumor and was detected in 62% of cases (n = 39). In addition, focal expression of COX-2 by malignant epithelial cells was observed in 23% of invasive adenocarcinoma. CONCLUSIONS: These results show that increased COX-2 expression in sporadic adenoma of the colon is common and is localized specifically to subepithelial intestinal myofibroblasts. These findings further support the hypothesis that myofibroblasts are important target cells for NSAID-mediated chemoprevention of colorectal cancer.     

Loss of colonic HLA antigens in familial adenomatous polyposis.

The loss of HLA antigens by neoplastic cells is considered important for tumor growth and metastasis, since it may allow tumors to escape immune surveillance. We studied the expression of HLA class I and II antigens in the colons of 10 patients with familial adenomatous polyposis (FAP), a condition which leads inevitably to colorectal cancer. Expression of HLA class antigens was studied by immunohistochemistry in (a) adenomas from patients with FAP, (b) histologically normal mucosa distant from the adenomas, and (c) histologically normal colonic mucosa from normal subjects. The expression of HLA class I and II antigens was decreased in histologically normal mucosa from FAP patients compared to normal controls. Adenomas showed a similar but quantitatively more pronounced reduction (or loss) of HLA antigen expression. The reduction of HLA expression in adenomas was comparable to that observed in sporadic colon carcinomas. This generalized suppression of HLA gene expression in the colon of FAP patients, which precedes the onset of overt histological manifestations of neoplasia, may be an important early event in colon carcinogenesis.     

Automated and quantitative immunocytochemical assays of Bcl-2 protein in breast carcinomas.

Expression of the bcl-2 gene was investigated in 218 human breast carcinomas by immunohistochemical analysis. Immunodetections were assessed using (1) frozen sections, (2) documented commercially available monoclonal antibody (bcl-2/124, Dako), (3) automation of immunoperoxidase technique (Ventana) and (4) quantitative evaluation of results by image analysis (SAMBA) and statistical analysis of quantitative data (BMDP software). Bcl-2 protein expression was correlated with current prognostic indicators and with molecular markers detected by the same procedure as for Bcl-2. It was shown that Bcl-2 expression is not related to patients'' age, tumour size and type or lymph node status, but an inverse relationship was observed between Bcl-2 and tumour grade (P < 0.0001). An inverse relationship was also observed between Bcl-2 expression and p53 (P < 0.0001), Ki67/MIB1 antigen- (P = 0.0012), and P-gp- (P = 0.002) positive immunoreactions. In contrast, anti-Bcl-2 positive reaction was significantly associated with ER-positive (P < 0.001) and with ER/PR-positive or ER/PR/pS2-positive immunoreactions (P < or = 0.005). Bcl-2 expression was independent of CD31 and cathepsin D expression. Thus, Bcl-2 protein, thought to be antiapoptotic, exhibits parodoxical expression in human breast carcinomas. It is strongly detected in low-grade tumours (well-differentiated) with low (MIB1) growth fraction, but is independent of the tumour progression (size, node status, CD31, and cathepsin D). Bcl-2 acting on apoptosis is related to p53 gene abnormalities in breast carcinomas. Bcl-2 protein expression may also be involved in response to endocrine therapy (associated to ER/PR/pS2 positive immunoreactions) and probably with chemoresistance mechanisms (inverse relationship with P-gp).