MIB1 proliferation index in breast infiltrating carcinoma: comparison with other proliferative markers and association with new biological prognostic factors

AIMS: In breast invasive carcinoma our objectives were I) to compare cellular proliferation determined by MIB1 index with S-phase fraction (SPF) assessed by flow cytometry and with mitotic index, and II) to examine the association of MIB1 index with classical and with new biological prognostic factors [bcl-2, p53, c-erbB-2 and cathepsin D (CD)]. METHODS AND RESULTS: From 102 cases of breast invasive carcinoma, 5-microm thick serial sections were cut from formalin-fixed, paraffin-embedded tissue blocks, and processed for detection of CD, c-erbB-2, p53, bcl-2, Ki-67 antigen MIB-1 and estrogen receptors (ER) and progesterone receptors (PR). SPF was measured by flow cytometry in fresh-frozen tissue samples taken from the carcinoma in each patient. MIB1 index was correlated with SPF (rho=0.45, p<0.0001) and with mitotic index (rho=0.42, p<0.0001). The MIB-1 index was positively associated with the histological grade (p=0.001), tumor size (p=0.04) and the presence of metastases in axillary lymph nodes (p=0.01). MIB1 was associated directly with p53 (p=0.045) and inversely with bcl-2 (p=0.0002). The MIB-1 index was not statistically associated with c-erbB-2. There was a weak association between MIBI index and stromal cell CD. The median MIB1 index was higher in tumors with moderate to strong CD staining of stromal cell, but the difference did not reach statistical significance (p=0.09). CONCLUSIONS: MIB1 index correlates with well established methods for assessing tumor proliferation and with parameters of an aggressive phenotype of tumor. MIB1 index is an effective and readily accessible method for assessing tumor proliferation in breast carcinoma.     

Pathologic significance of proliferative activity and oncoprotein expression in astrocytic tumors

OBJECTIVE: To clarify the clinicopathologic significance of immunohistochemistry for proliferative activity and oncoprotein expression in astrocytic tumors. STUDY DESIGN: Ninety-seven cases of brain astrocytic tumors with histologic grading and follow-up data were investigated with immunohistochemistry and image analyzer to detect the expression of proliferating cell nuclear antigen (PCNA), silver-binding nucleolar organizer regions (AgNORs) and several oncoproteins. RESULTS: PCNA was significantly related to AgNORs, grading and prognosis of astrocytomas. The frequency of mutant p53 protein expression was higher in grade 2-4 astrocytomas than in grade 1. Epidermal growth factor (EGF) (37.1%), EGF receptor (83.5%) and p21ras (42.3%) expression levels were related to neither the grade nor prognosis of the tumors. The positive ratios of p53 antibodies were higher in grades 2-4 than in grade 1, and the intensities correlated with PCNA but not with prognosis. CONCLUSION: Aberrations of c-erbB-2, p21ras, EGF and EGF receptor might be early events in the initiation and progression of astrocytomas, whereas p53 overexpression is involved in all the stages. Immunohistochemical detection had no prognostic value. PCNA could be important to the evaluation of astrocytoma malignancy.     

Prognostic factors affecting disease-free survival rate following surgical resection of primary breast cancer.

In order to identify the prognostic factors that significantly influence the disease-free survival rate after surgical resection of primary breast cancers, we determined tumour and lymph node grades, and immunohistochemical staining for estrogen and progesterone receptors (ER and PR), c-erbB-2, p53, bcl-2, bax and PCNA in 76 patients. Univariate analysis showed that increased grade of tumour and lymph nodes, negative immunostaining for ER, positive immunostaining for c-erbB-2, and a high PCNA index (> or = 30%) negatively influenced the disease-free survival rate, but PR, p53, bcl-2 and bax had no predictive value. Although p53 was not an independent prognostic factor by itself, the combination of p53, bcl-2, and bax proved to correlate with the disease-free survival, with the best prognosis noted in tumours negative for p53 and positive for both bcl-2 and bax, intermediate prognosis in tumours negative for p53 and positive for either bcl-2 or bax and worst prognosis in tumors negative for p53 as well as bcl-2 and bax. Tumour grade correlated positively with PCNA index, while positive staining for ER correlated negatively with tumour grade as well as with PCNA index, although this was statistically insignificant. Immunostaining of breast cancers for bcl-2 correlated negatively with tumour grade and PCNA index. Immunostaining for c-erbB-2 correlated positively with PCNA but not with tumour grade. Immunostaining for p53 tended to correlate positively with PCNA, but not with tumour grade. Immunostaining for PR and bax did not correlate with tumour grade and PCNA index. These results suggest that in addition to tumour size and lymph node involvement, immunostaining for ER, c-erbB-2, and a high PCNA index are important prognostic factors in human breast cancer. Wild-type p53 with preserved bcl-2 and bax gene products is also a favorable prognostic factor indicating breast cancer at an early stage of cancer progression.     

Immunohistochemical expression of the p53, mdm2, p21/Waf-1, Rb, p16, Ki67, cyclin D1, cyclin A and cyclin B1 proteins and apoptotic index in T-cell lymphomas

Fifty-seven cases of T-cell lymphomas (TCL) including 5 lymphoblastic (T-LBL) and 52 peripheral TCL (PTCL) were analyzed by immunohistochemistry for the expression of p53, mdm2, p21, Rb, cyclin D1, cyclin A, cyclin B1, and Ki67/MIB1 proteins and 39/52 PTCL were also analyzed for the expression of p16 protein and for the presence of apoptotic cells by the TUNEL method. The aim was to search for abnormal immunoprofiles of p53 and Rb growth control pathways and to determine the proliferative activity and the apoptotic index of TCL. Abnormal overexpression of p53, p21 and mdm2, in comparison to normal lymph nodes, was found in 12/57, 10/57 and 2/57 cases of TCL, respectively. Abnormal loss of Rb and p16 expression was found in 1/57 and 2/39 cases, respectively, whereas abnormal overexpression of cyclin D1 was not detected in any of the 57 cases. Our data revealed entity-related p53/p21/mdm2 phenotypes. Indeed, most nodal and cutaneous CD30+ anaplastic large cell lymphomas (ALCL) showed concomitant overexpression of p53 and p21 proteins (7/8 cases), and mdm2 was overexpressed in 2 p53-positive nodal ALCL. In contrast, overexpression of p53 was found in 3/17 cases of nodal peripheral TCL unspecified (PTCL-UC) and 2/7 non-ALCL cutaneous pleomorphic TCL. Overexpression of p21 protein was detected in 2/3 p53-positive PTCL-UC and in 1/2 p53-positive non-ALCL cutaneous pleomorphic TCL. Finally, all the remaining 25 cases of TCL did not show p53 and p21 overexpression. Overall, the p53+/p21+ phenotype in 10/57 TCL suggests wild-type p53 capable of inducing p21 expression. The highest apoptotic index (AI) was found in ALCL and a positive correlation between apoptotic index and Ki67 index (p<0.001) was detected. Ki67, cyclin A and cyclin B1 expression was found in all 57 TCL and on the basis of the combined use of these 3 variables, 3 groups of proliferative activity could be determined: a) high in ALCL and T-LBL, b) low in mycosis fungoides (MF) and gammadelta hepatosplenic TCL, and c) intermediate in the remaining TCL entities. The proliferative activity in the 12 p53 overexpressing cases was higher in comparison to the 45 p53-negative cases. Ki67 expresion in more than 25% of tumour cells showed significant correlation with p53 overexpression (p<0.001). Rb expression tended to be parallel to Ki67, cyclin A and cyclin B1 expression in all but one case of nodal PTCL-UC which displayed loss of RB expression. Interestingly, this case was p53-negative, whereas the p53-positive cases were Rb-positive. These findings suggest that different pathogenetic routes may function in some TCL, involving either the p53 or, less frequently, the Rb pathways.     

Immunohistochemical evaluation of pRb2/p130, VEGF, EZH2, p53, p16, p21waf-1, p27, and PCNA in Barrett's esophagus

Control of the G1/S-phase transition as well as angiogenic switch are two of the most studied mechanisms in cancer. The current study examined the correlation between the immunohistochemical expression of pRb2/p130, VEGF, EZH2, p53, p16, p21waf-1, p27, and PCNA in Barrett's esophagus (BE). Overall, p53 showed a much higher expression in BE patients (up to 50%) than in controls (1-10%) (P < 0.005). Also p21 showed a downregulation in BE when compared to normal esophagus (70% of cells vs. 65%), but the difference did not show any statistical significance (P = 0.45). pRb2/p130 was detected in 80% of cells in normal controls, but showed positive in only 20% of cells in BE biopsies. Additionally, Rb2/p130 expression was inversely correlated to that of VEGF, EZH2, and PCNA (P < 0.0001, P = 0.0032, P < 0.001, respectively). p27 stained more intensely and in a widespread manner (70%) cells in normal esophageal tissues but about only 30% in BE samples (P < 0.001). Lastly, in accordance with other reports, we also found p16 expressed by immunohistochemistry at high levels in normal controls and at low levels in BE (P < 0.001). In conclusion, p16, p21, p27, and p53 staining confirmed previously published data. Interestingly, pRb2/p130 expression was found significantly decreased in metaplastic epithelium compared to normal controls and showed significant inverse correlation with the expression of other markers, such as VEGF, EZH2, and PCNA. These data, taken together, indicate that these molecular events occurring in Barrett's metaplasia (BM) may represent one of the many steps taking place during esophageal malignant progression such as impairment of cell-cycle control, altered differentiation, and unbalanced angiogenesis.     

The expression of PCNA, c-erbB-2, p53, ER and PR as well as atypical hyperplasia in tissues nearby the breast cancer

To examine the proper margin for breast conservative surgery in Chinese women population. 40 breast cancer specimens were collected and each sample was dissected into several groups: primary tumor group, 1 cm paracarcinoma, 2 cm paracarcinoma, 3 cm paracarcinoma and excessive 3 cm paracarcinoma groups. The immunohistochemistry staining was performed to measure the expression levels of proliferating cell nuclear antigen (PCNA), c-erbB-2, p53, estrogen receptor (ER) and progesterone receptor (PR). The gene expressions of PCNA, c-erbB-2, and p53 gradually decreased with the increased distance from primary tumor (P < 0.05). The 1 and 2 cm paracarcinoma group (no differences between the two, P > 0.05) showed higher risk factors (c-erbB-2, p53) than the 3 cm and excessive 3 cm paracarcinoma groups (P < 0.05). The expression of PCNA, ER, and PR showed no correlation with cancer progression (P > 0.05). Beyond the paracarcinoma 2 cm distance, the tissues showed significant decreases in tumor gene expression, which could represent the appropriate region for breast conservative surgery.     

Cooperation between p53 and p130(Rb2) in induction of cellular senescence

To determine pathways cooperating with p53 in cellular senescence when the retinoblastoma protein (pRb)/p16INK4a pathway is defunct, we stably transfected the p16INK4a-negative C6 rat glioma cell line with a temperature-sensitive mutant p53. Activation of p53(Val-135) induces a switch in pocket protein expression from pRb and p107 to p130(Rb2) and stalls the cells in late G1, early S-phase at high levels of cyclin E. Maintenance of the arrest depends on the functions of p130(Rb2) repressing cyclin A. Inactivation of p53 in senescent cultures restores the pocket proteins to initial levels and initiates progression into S-phase, but the cells fail to resume proliferation, likely due to DNA damage becoming apparent in the arrest and activating apoptosis subsequent to the release from p53-dependent growth suppression. The data indicate that p53 can cooperate selectively with p130(Rb2) to induce cellular senescence, a pathway that may be relevant when the pRb/p16INK4a pathway is defunct.     

Cross‐talk between T‐Ag presence and pRb family and p53/p73 signaling in mouse and human medulloblastoma

The formation and progression of mudulloblastoma (MB) is poorly understood. However, somatic inactivation of pRb/p105, in combination with a somatic or a germ‐line TP53 inactivation, leads to MB in a mouse model. Presently, there is no specific evidence of pathway/s alterations for the other two members of the retinoblastoma family, pRb2/p130 and/or p107 in MB. JC virus (JCV) is a human polyomavirus. Although there is no firm evidence that this virus plays a causal role in human neoplasia, it has been clearly proven that JCV is highly oncogenic when injected into the brain of experimental animals. The mechanism of JCV‐induced tumorigenesis is not entirely clear. However, several studies relate the oncogenic properties of JCV mainly to its early protein large T‐antigen (T‐Ag), which is able to bind and inactivate both TP53 and Rb family proteins. Here, we compared the protein expression profiles of p53, p73, pRb family proteins, and PCNA, as main regulators of cell proliferation and death, in different cell lines of mouse primitive neuroectodermal tumors (PNET), either T‐Ag‐positive or ‐negative, and in human MB cell lines. Our goal was to determine if changes in the relative expression of these regulators could trigger molecular perturbations underlying MB pathogenesis in mouse and human cells. Our results support that the presence of JCV T‐Ag may interfere with the expression of pRb family proteins, specific p73 isoforms, and p53. In turn, this “perturbation” may trigger a network of signals strictly connected with survival and apoptosis. J. Cell. Biochem. 110: 182–190, 2010. © 2010 Wiley‐Liss, Inc.     

Immunohistochemical analysis for cell proliferation-related protein expression in small cell carcinoma of the esophagus; a comparative study with small cell carcinoma of the lung and squamous cell carcinoma of the esophagus

Small cell carcinoma is a rare neoplasm in the esophagus. To evaluate cell proliferation activity and its underlying mechanisms in this tumor, we examined immunohistochemically 5 cases of small cell carcinoma of the esophagus (SCCE) for expressions of tumor suppressor proteins, oncoproteins and cell proliferation markers including p53, p21WAF1/CIP1, retinoblastoma (Rb) protein, bcl-2, Ki-67 and PCNA, and compared the results with those of 5 cases of small cell carcinoma of the lung (SCCL) and 10 cases of squamous cell carcinoma of the esophagus (SQCE). The prevalence and labeling index of p53-immunoreactivity tended to be higher in SCCE (4/5; 56.6%) and SCCL (4/5; 79.9%) than in SQCE (6/10; 48.8%). Expression of p21WAF1/CIP1 was observed in 2 of 10 cases of SQCE. In contrast, its expression could not be detected in any cases of SCCE and SCCL examined. Expression of Rb protein was observed in 9 out of 10 cases of SQCE, but not in any cases of SCCE and SCCL. SCCE and SCCL showed more frequent and intense immunoreactivity for bcl-2 than SQCE. In expression of cell proliferation markers (Ki-67 and PCNA), no remarkable difference was observed among SCCE, SCCL and SQCE. These results suggest that SCCE and SCCL could share some genetic alternations including mutation of p53, loss of Rb gene and overexpression of bcl-2, and these may be related to the similar biological potentials between the two. Furthermore, SCCE was different from SQCE in expression of Rb protein and bcl-2, and these two types of esophageal carcinoma could arise through different molecular mechanisms.     

Immunohistochemical localization and correlation of p53 and PCNA expression in breast carcinoma

The object of the present study is to detect the p53 tumour suppressor gene and proliferation cell nuclear antigen (PCNA) expression in breast carcinoma by immunohistochemistry and correlate them with the prognostic parameters. Total 35 cases of primary breast carcinoma were studied and classified histologically. Paraffin sections were stained by using monoclonal antibody D07 for p53 protein and PC-10 for PCNA. Out of 35 cases, 16 (45.7%) were p53 positive and 25 (71.4%) were PCNA positive. The mean PCNA labelling index (PCNA LI +/- SD) was 58.97 +/- 22.72 in tumors positive for both p53+ and PCNA+ while cases negative for p53- and positive for PCNA+ has higher PCNA LI +/- SD (59.24 +/- 18.97). The difference in the two groups was not significant. Most cases were positive for both p53+ and PCNA+ in the age group < 30 with higher mean PCNA LI +/- SD (62.20 +/- 27.13) than in the group > 30 (57.88 +/- 18.47). In the pre-menopausal group 57.1% cases were positive for p53+ with higher PCNA LI +/- SD (59.94 +/- 24.22). Maximum p53 and PCNA positivity was observed in grade III tumors (63.2% and 84.2%). The mean PCNA LI +/- SD was also highest in grade III carcinomas (66.83 +/- 13.97). No significant correlation was found between p53 and PCNA status with morphological type and tumour size except that logistic regression showed a positive correlation with tumour grade. Therefore the present study suggests that both p53 expression and PCNA are markers of poor differentiation in breast cancer.     

Status of p53, p21, mdm2, pRb proteins, and DNA methylation in gonocytes of control and gamma-irradiated rats during testicular development

In fetal and newborn rat testes, gonocytes, which stop cycling for about 8 days, become highly radiosensitive. The presence of p53, p21, mdm2, and pRb, which are involved in cell cycle, apoptosis control, or both, were studied by immunohistochemistry to determine if their expression is related to this radiosensitivity. A strong cytoplasmic expression of p53 and p21 was detected. Cytoplasmic expression of p53 occurred only in arrested gonocytes, whereas that of p21 was observed before and after the block. P21 was found to colocalize with mitochondria. No expression of mdm2 was detected and pRb was present only when the gonocytes started cycling again. In animals exposed to 1.5 Gy of gamma-irradiation at Day 19 postcoitum, p53 expression was prolonged in time, whereas no change was observed in p21 amounts and localization, compared with controls. Using antibodies against 5-methyl cytosine, it was shown that gonocyte DNA passed from a hypomethylated to a methylated status 1 day after gonocytes stopped cycling. A prolonged survival of gonocytes after exposure to radiation was followed by their progressive apoptosis, which finally involved the entire gonocyte population between Days 6 and 12 postpartum. The elevated but delayed sensitivity of gonocytes to genotoxic stress may be related to the unusual expression of p53 and p21, which may itself be related to the large DNA methylation changes.     

Microsatellite Alterations and Protein Expression of 5 Major Tumor Suppressor Genes in Gastric Adenocarcinomas

PURPOSE: In gastric adenocarcinoma (GC), the major tumor suppressor genes (TSGs) such as p16, PTEN, Rb, E-cadherin, and p53, may play important roles in various regulatory pathways and in tumor suppression. This study evaluated the loss of heterozygosity (LOH) of microsatellite and protein expression of 5 TSGs and the results were examined for their correlation with clinicopathological factors. METHODS: LOH analysis was carried out using polymerase chain reactions with 15 polymorphic microsatellite markers of 5 chromosomes containing TSGs in 100 surgically resected tumors. Protein expression was evaluated by immunohistochemistry (IHC). RESULTS: LOH was detected in 83% of GCs. LOH of 9p21, 10q23, 13q14, 16q22, and 17p13 were detected in 26%, 31%, 24%, 22%, and 35% of cases, respectively. Protein expression of p16, PTEN, Rb, E-cadherin, and p53 were found to be 31%, 39%, 28%, 32%, and 46% of cases. Advanced GCs showed significantly higher rates of 17p13 LOH and p53 expression. 9p21 LOH and E-cadherin IHC were correlated with higher tumor grade. Lymph node metastasis was correlated with the LOH of 9p21, 16q22, and 17p13 and IHC of the Rb and p53. A higher stage was correlated with 10q23 and 17p13 in LOH and p53 for IHC. CONCLUSION: These results suggest that LOH and protein expression of various TSGs are important in carcinogenesis and tumor invasion. Additionally, LOH and IHC may be useful clinical indicators for determining the prognosis of patients with GCs. In particular, the 17p13 LOH and p53 for IHC can be applied as simple evaluations in the clinic.     

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.     

Glycoprotein CD44 expression in benign, premalignant and malignant epithelial lesions of the larynx: an immunohistochemical study including correlation with Rb, p53, Ki-67 and PCNA.

CD44 is an integral membrane glycoprotein that has diverse functions in cell-cell and cell-substrate interactions. It has been suggested that it may be a determinant of metastatic and invasive behavior in carcinomas. The immunohistochemical expression of CD44 was examined in a series of 34 squamous cell carcinomas, 13 in situ carcinomas, 35 cases with various degrees of epithelial dysplasia, 10 papillomas and 17 cases of keratosis. We used the monoclonal mouse anti-human phagocytic glycoprotein-1 CD44 (clone DF 1485), on formalin-fixed, paraffin-embedded tissue. CD44 expression was correlated with the expression of Rb and p53 proteins, with the proliferative indices Ki-67 and PCNA as well as with conventional clinicopathological data. The mean value of CD44 expression was 78.84 in squamous cell carcinomas, 78.04 in situ carcinomas, 54.93 in dysplasia, 26.8 in papillomas and 24.97 in keratosis. There was no significant difference of CD44 expression between in situ and invasive carcinomas. However, a strong difference of reaction between carcinomas and the other cases was observed. CD44 expression was statistically higher in dysplastic lesions than the cases of keratosis (p < 0.0001) and papillomas (p = 0.01). In the group of invasive carcinomas, CD44 expression was statistically correlated with pRb (p = 0.011), while in preinvasive lesions it was correlated with PCNA (p = 0.016). The relationship with the degree of dysplasia or grade of carcinoma and p53 protein expression was insignificant. These observations suggest that CD44 expression may be involved in the multiple mechanism of the development and progression of laryngeal lesions and may help to predict the risk of transformation of the benign or precancerous lesions to cancer.     

Relationship between AgNOR proteins, Ki-67 antigen, p53 immunophenotype and differentiation markers in archival breast carcinomas.

The present study investigated (i) the relationship between standardised morphometric AgNOR parameters (argyrophilic nucleolar organiser region-associated proteins) and MIB1 growth fraction, and (ii) their correlation with immunohistochemical p53, sex steroid receptor status and histopathological differentiation grade in serial paraffin sections from 39 breast carcinomas. Ten sections were double-stained for AgNOR/MIB1. AgNOR parameters correlated significantly with MIB1 growth fraction and p53 protein expression. Significant inverse correlation was found between proliferation markers and oestrogen/progesterone receptor status and histopathological grade. AgNOR expression was significantly higher in cycling (MIB1 positive) tumour cells, than in resting (MIB1 negative) ones, however with exceptions. We conclude, that standardised AgNOR parameters correlate with markers of increased malignant potential in breast carcinomas. However, AgNORs seem to reflect proliferation independent cellular and nucleolar activity of tumour cells, as well. We recommend the use of standardised AgNOR analysis for obtaining sound results in routine paraffin sections.     

Expression of Mina53 and its significance in gastric carcinoma

AIM: To study the expression of Mina53 and its relationships with clinicopathological characteristics, antioncogene inactivation and tumor proliferation in human gastric carcinoma, and to explore the role of Mina53 in carcinogenesis and tumor progression. METHODS: Expression of Mina53 and proliferating cell nuclear antigen (PCNA) was determined in gastric carcinoma (n=79), gastric dysplasia (n=21) and normal gastric tissues (n=20), while p53 was measured in gastric carcinoma tissues by immunohistochemistry. RESULTS: Mina53 was negatively expressed in all normal mucosa tissues. Dysplasia specimens showed weakly positive staining for Mina53 in 3 of 21 cases. Elevated expression of Mina53 was observed in 72 (91.1%) of the gastric carcinomas. No significant associations were found between Mina53 and clinicopathological characteristics such as sex, age, histological differentiation, distant metastasis and lymph node metastasis (p>0.05). There was a significant association with depth of invasion (X2=5.385, p<0.05) and TMN stage (X2=6.255, p<0.05). In gastric carcinoma, positive staining for p53 was detected in 53 of 79 cases (67.1%), showing a significant association with Mina53 (X2=5.161, p<0.05). The mean (+/- SD) PCNA labeling index for gastric carcinoma was 39.47+/-16.92%. Mina53 expression was positively associated with PCNA level (r=0.756, p<0.01). CONCLUSION: Mina53 was overexpressed in gastric carcinoma and associated with tumor proliferation and antioncogene inactivation. Mina53 could therefore play an important role in the carcinogenesis and progression of gastric carcinoma.