Prognostic impact of p21/waf1/cip1 in colorectal cancer

A pathologic complete response of rectal cancer to preoperative combined-modality therapy results in improved oncological outcome compared with those who achieve no downstaging on the basis of preoperative endorectal ultrasonography

BACKGROUND

Preoperative combined-modality therapy (CMT) is the preferred treatment for locally advanced rectal cancer (endorectal ultrasonography [ERUS] T3-4, N1, or clinically bulky) and achieves a pathologic complete response (pCR) in 4% to 33% of patients. However, the prognostic significance of pCR remains unclear.

METHODS

A prospectively collected database was queried to identify 200 patients with locally advanced disease treated from 1992 to 2002. The pCR group was defined as having no evidence of viable tumor on pathologic analysis. The no-downstaging group was defined as no difference between the pre-CMT ERUS stage and the pathologic stage. Those achieving some downstaging but not pCR were excluded. Patients were treated with CMT (5040 cGy of radiation and 5-fluorouracil-based chemotherapy) followed by surgery, and 51 (85%) in the pCR group and 129 (92%) in the no-downstaging group (P = .1) received postoperative chemotherapy. Recurrence-free survival (RFS) and overall survival (OS) were determined by using the Kaplan-Meier method.

RESULTS

The median follow-up was 38.6 months (range, 18.2-124.9 months). The pCR (n = 60) and control (n = 140) groups were similar in age (P = .6), sex (P = .4), distance of the tumor from the anal verge (P = .3), pre-CMT ERUS stage (P = .2), and comorbidities (P = .2). The 5-year RFS was 96% and 54% in the pCR and control groups, respectively (P < .00001); the 5-year OS was 90% and 68% (P = .009). Sphincter-preservation rates were higher in the pCR group (P = .01).

CONCLUSIONS

Rectal cancer patients with pCR after preoperative CMT have improved RFS, OS, and sphincter preservation compared with patients without downstaging. Because pCR seems to be associated with better outcome, an understanding of the factors governing the response to CMT should be pursued.

Genetic dissection of apoptosis and cell cycle control in response of colorectal cancer treated with preoperative radiochemotherapy

Background

In previous analyses we identified therapy-induced upregulation of the CDK inhibitor p21^CIP/WAF-1 and consequently decreased tumor cell proliferation or loss of Bax as adverse factors for survival in rectal cancer treated with radiochemotherapy. Here, we address the individual role of p53 and its transcriptional targets, p21^CIP/WAF-1 and Bax, on apoptosis induced by individual components of multimodal anticancer therapy, i.e. 5-fluorouracil (5-FU), ionising γ-radiation (IR) and heat shock/hyperthermia.

Methods

We analysed tumor samples 66 patients with rectal carcinoma treated by a neoadjuvant approach with radiochemotherapy ± heat shock/hyperthermia for the expression and mutation of p53 and the expression of p21^CIP/WAF-1 and Bax. These data were correlated with the tumor response. The functional relevance of p53, p21^CIP/WAF-1 and Bax was investigated in isogeneic HCT116 cell mutants treated with 5-FU, IR and heat shock.

Results

Rectal carcinoma patients who received an optimal heat shock treatment showed a response that correlated well with Bax expression (p = 0.018). Local tumor response in the whole cohort was linked to expression of p21^CIP/WAF-1 (p < 0.05), but not p53 expression or mutation. This dichotomy of p53 pathway components regulating response to therapy was confirmed in vitro. In isogeneic HCT116 cell mutants, loss of Bax but not p53 or p21^CIP/WAF-1 resulted in resistance against heat shock. In contrast, loss of p21^CIP/WAF-1 or, to a lesser extent, p53 sensitized predominantly for 5-FU and IR.

Conclusion

These data establish a different impact of p53 pathway components on treatment responses. While chemotherapy and IR depend primarily on cell cycle control and p21, heat shock depends primarily on Bax. In contrast, p53 status poorly correlates with response. These analyses therefore provide a rational approach for dissecting the mode of action of single treatment modalities that may be employed to circumvent clinically relevant resistance mechanisms in rectal cancer.

Cell cycle related proteins as prognostic parameters in radically resected non-small cell lung cancer

BACKGROUND

Experimental evidence suggests that lung cancer development and progression can be linked to an increased proliferation rate.

AIMS/METHODS

To evaluate the immunohistochemical expression of seven components of the cell cycle machinery in a series of well characterised non-small cell lung cancer (NSCLC) specimens (n = 105).

RESULTS

Multivariate analysis revealed that simultaneous loss of expression of three of these factors--cyclin D1, the cyclin dependent kinase inhibitor p16, and the tumour suppressor retinoblastoma protein Rb2/p130--correlated with survival, confirming the hypothesis that the cyclin D1-p16-retinoblastoma tumour suppressor pathway is inactivated in most lung cancer samples.

CONCLUSIONS

These results suggest that loss of control of cell cycle checkpoints is a common occurrence in lung cancer and support the idea that functional cooperation between different cell cycle regulatory proteins constitutes another level of regulation in cell growth control and tumour suppression.

A Predictive Model of Rectal Tumor Response to Preoperative Radiotherapy Using Classification and Regression Tree Methods

PURPOSE

The ability to predict rectal tumor response to preoperative radiotherapy before treatment would significantly impact patient selection. In this study, classification and regression tree (CART) methods were used to model tumor response to preoperative conformal high-dose rate brachytherapy by assessing the predictive value of vascular endothelial growth factor (VEGF), Bcl-2, p21, p53, and APAF-1.

EXPERIMENTAL DESIGN

Immunohistochemistry was used to detect VEGF, Bcl-2, p21, p53, and APAF-1 from 62 pretreatment rectal tumor biopsies. Scores were assigned as percentages of positive tumor cell staining and were used in CART analysis to identify the proteins that best predicted response to radiotherapy. Ten-fold cross-validation was used to prevent overfitting and multiple cross-validation experiments were run to estimate the prediction error.

RESULTS

Postoperative pathologic evaluation of the irradiated tumor bed revealed 43 responsive tumors [20 with complete response (T(0)) and 23 with partial response] and 19 nonresponsive tumors. The optimal tree resulting from CART analysis had five terminal nodes with a misclassification rate of 18%. Of the five proteins selected for their predictive value, VEGF and Bcl-2 contributed most to the classification of responsive and nonresponsive tumors. All 10 tumors with no VEGF were completely responsive (T(0)) to radiotherapy; 85% of those with VEGF and negative for Bcl-2 were responsive to therapy.

CONCLUSIONS

VEGF and Bcl-2 status in pretreatment rectal tumor biopsies may be predictive of response to preoperative high-dose rate brachytherapy.

Different cooperating effect of p21 or p27 deficiency in combination with INK4a/ARF deletion in mice

The control exerted by the INK4a/ARF locus on cellular proliferation is crucial to restrict tumor development. In agreement with this, mice with defects in this locus are highly tumor prone. However, the potential contribution of other pathways in modulating tumorigenesis in the absence of INK4a/ARF is largely unexplored. In the present study, we investigated the consequences of the combined loss of either of two cyclin-dependent kinase inhibitors, p21 and p27, in cooperation with deletion of the INK4a/ARF locus. Our results show a clear differential effect in tumorigenesis depending on the CKI that is absent. The absence of p21 produced no overt alteration of the lifespan of the INK4a/ARF-null mice, although it modified their tumor spectrum, causing a significant increase in the incidence of fibrosarcomas and the appearance of a small number of rhabdomyosarcomas. In contrast, deficiency of p27 resulted in a significant increase in lethality due to accelerated tumor development, especially in the case of T-cell lymphomas. Finally, combined deficiency of INK4a/ARF and p27 resulted in a significant increase in the number of metastatic tumors. These results demonstrate genetically the oncogenic cooperation between defects on INK4a/ARF and p27, which are common alterations in human cancer.

Expression of p27 in residual rectal cancer after preoperative chemoradiation predicts long-term outcome

BACKGROUND

Compared with surgery alone, preoperative radiotherapy and 5-fluorouracil-based chemotherapy (combined-modality therapy; CMT) improves outcomes in patients with locally advanced rectal cancer. Although numerous studies have focused on identifying molecular markers of prognosis in the primary rectal cancer before CMT, our aim was to identify markers of prognosis in residual rectal cancer after preoperative CMT.

METHODS

Sixty-seven patients with locally advanced (T3-4 and/or N1) rectal cancer were treated with preoperative radiotherapy (median, 5040 cGy) with or without 5-fluorouracil-based chemotherapy. Residual tumor in the resected specimen, available for 52 patients, was analyzed for tumor-node-metastasis stage, lymphovascular and/or perineural invasion, and immunohistochemical expression of p27, p21, p53, Ki-67, retinoblastoma gene, cyclin D1, and bcl-2. Recurrence-free survival (RFS) was determined by the Kaplan-Meier method and compared by the log-rank test.

RESULTS

With a median follow-up of 69 months, the overall 5-year RFS was 74%. RFS was significantly worse for patients with positive p27 expression (P = .005), T3-4 tumors (P = .02), and positive lymph nodes (P = .04) in the irradiated specimen. On multivariate analysis, positive p27 expression remained an independent negative prognostic factor for RFS (P = .04). None of the other proteins was significantly associated with RFS.

CONCLUSIONS

Our results indicate that positive p27 expression in rectal cancer after preoperative chemoradiation is an independent negative predictor of RFS. Expression of p27 in the residual rectal cancer may therefore identify patients with disease likely to be refractory to standard therapy and for whom investigational approaches should be strongly considered.

Expression profiling of colorectal carcinomas using tissue microarrays: cell cycle regulatory proteins p21, p27, and p53 as immunohistochemical prognostic markers in univariate and multivariate analysis

With the rapidly growing understanding of tumor biology, molecular staging of cancer is expected to improve prognostication. This would be particularly important for cancers amenable to adjuvant treatment, such as colorectal carcinomas. To generate data for this, the tissue microarray technique may prove useful. Tissue microarrays were constructed with triplicate cores (0.6 mm diameter) from the invasive margins of a consecutive single-institution series of 184 colorectal carcinomas. Immunostaining for p53, p21, p27, Ecadherin, and beta-catenin was scored. Tumor cell proliferation was assessed by mitotic indices and Ki-67 labeling, apoptosis by quantification of apoptotic bodies. Reduced nuclear immunostaining for p21 (<10%) and p27 (< or =50%) and reduced membranous expression of Ecadherin were significantly associated with a poorer clinical course by univariate analysis. beta-catenin immunostaining had no prognostic impact. Mitotic and apoptotic indices as well as Ki-67 labeling below the median were indicators of poor prognosis. Complete absence of p53 nuclear staining was a significant adverse prognostic factor. By Cox regression, p53 = 0%, p53 = 0%, in combination with p27 < or = 50%, the mitotic index and the combined mitotic and apoptotic index added prognostic information to UICC stage. The authors found that growth pattern, lymphohistiocytic response, lymphatic permeation, and venous spread, too, each was a strong prognosticator in addition to UICC stage. The results support that tissue microarrays are a useful tool for screening immunohistochemical markers for prognostic use. An immunopanel of p21, p27, and p53 could be useful for prognostication in colorectal carcinoma in addition to UICC stage.

P21Cip1 is a critical mediator of the cytotoxic action of thymidylate synthase inhibitors in colorectal carcinoma cells

We have demonstrated previously that interferon (IFN)-gamma sensitizes human colon carcinoma cell lines to the cytotoxic effects of 5-fluorouracil combined with leucovorin and to the thymidylate synthase inhibitor, ZD9331, dependent on thymineless stress-induced DNA damage, independent of p53. Here we demonstrate that the cyclin-dependent kinase (CDK) inhibitor p21(Cip1) regulates thymineless stress-induced cytotoxicity in these cells. HCT116 wild-type (wt) and p53-/- cells underwent apoptosis and loss in clonogenic survival when exposed to ZD9331, whereas p21Cip1-/- cells were resistant. In contrast, IFN-gamma induced marked cytotoxicity in p21Cip1-/- cells only. ZD9331 induced p21Cip1 up-regulation in all of the cell lines examined, as did thymidine deprivation in thymidylate synthase-deficient (thymidylate synthase-) cells. Furthermore, selective induction of p21Cip1 in RKO was sufficient to induce apoptosis. P21Cip1, cdk1, cdk2, and cyclin E mRNA expression increased coincident with S-phase accumulation in HT29 cells treated with ZD9331 or 5fluorouracil/leucovorin, as demonstrated by cDNA microarray analyses. Cell cycle analyses revealed that HCT116 wt and p21Cip1 -/- cells accumulated in S phase within 24 h of ZD9331 exposure; however, wt cells exited S-phase more rapidly, where apoptosis occurred before mitosis, either in late S or G2. Finally, the CDK inhibitor roscovitine potentiated the cytotoxic activity of ZD9331 in both wt and p21Cip1-/- cells, strongly suggesting a role for p21Cip1-dependent CDK inhibition in cytotoxicity induced by thymidylate synthase inhibition. In summary, p21Cip1 positively regulates the cytotoxic action of thymidylate synthase inhibitors, negatively regulates the cytotoxic action of IFN-gamma, and enhances S-phase exit after thymineless stress, possibly via interaction with CDK-cyclin complexes.

Cyclin D1 genetic heterozygosity regulates colonic epithelial cell differentiation and tumor number in ApcMin mice

Constitutive beta-catenin/Tcf activity, the primary transforming events in colorectal carcinoma, occurs through induction of the Wnt pathway or APC gene mutations that cause familial adenomatous polyposis. Mice carrying Apc mutations in their germ line (ApcMin) develop intestinal adenomas. Here, the crossing of ApcMin with cyclin D1-/- mice reduced the intestinal tumor number in animals genetically heterozygous or nullizygous for cyclin D1. Decreased tumor number in the duodenum, intestines, and colons of ApcMin/cyclin D1+/- mice correlated with reduced cellular proliferation and increased differentiation. Cyclin D1 deficiency reduced DNA synthesis and induced differentiation of colonic epithelial cells harboring mutant APC but not wild-type APC cells in vivo. In previous studies, the complete loss of cyclin D1 through homozygous genetic deletion conveyed breast tumor resistance. The protection of mice, genetically predisposed to intestinal tumorigenesis, through cyclin D1 heterozygosity suggests that modalities that reduce cyclin D1 abundance could provide chemoprotection.

Immunohistochemical study of cell cycle-associated proteins in adenocarcinoma of the uterine cervix treated with radiotherapy alone: P53 status has a strong impact on prognosis

PURPOSE

Because the incidence of adenocarcinoma of the uterine cervix has recently risen, the evaluation of radiotherapy (RT) for this disease has become an increasingly urgent matter. We analyzed the expression of the cell cycle-associated proteins p53, p27, p21/waf1/cip1, and cyclin D1 in cervical adenocarcinomas in correlation with the prognostic significance in tumors treated with RT alone.

METHODS AND MATERIALS

The expression of p53, p27, p21/waf1/cip1, and cyclin D1 was studied using an immunohistochemical method in 53 cases of cervical adenocarcinoma treated only with RT. Patients received RT alone between 1965 and 1994. The mean patient age was 61.8 +/- 12.6 years (range, 36-82 years). The number of patients with Stage I, II, III, and IVA disease was 6, 16, 28, and 3, respectively.

RESULTS

The number of patients with p53, p27, p21/waf1/cip1, and cyclin D1 positive tumors was 24, 18, 22, and 8, respectively; no statistically significant correlation was noted. The 5-year disease-free survival rate of p53-positive patients was 30%, significantly lower than the 62% for the p53-negative patients (p = 0.02); no statistically significant correlation was noted between disease-free survival and p27, p21/waf1/cip1, and cyclin D1 expression. No statistically significant correlation was observed between local control and expression of any of the proteins.

CONCLUSION

Expression of p53 protein has a statistically significant impact on disease-free survival in adenocarcinoma of the uterine cervix treated with RT alone. However, the clinical significance of p27, p21/waf1/cip1, and cyclin D1 protein expression was not obvious.

Analysis of cell cycle regulator proteins in non-small cell lung cancer

BACKGROUND/AIMS

Abnormalities of the proteins involved in cell cycle checkpoints are extremely common among almost all neoplasms. This study aimed to investigate the expression of four components of the cell cycle machinery-p21, p16, p53, and proliferating cell nuclear antigen (PCNA)-in non-small cell lung cancer (NSCLC).

METHODS

The expression of p21, p16, p53, and PCNA was examined in 68 well characterised NSCLC specimens using immunohistochemistry. The coregulation of these proteins and their influence on survival were analysed using both univariate and multivariate analyses.

RESULTS

By univariate analysis, the expression of all the proteins examined, except for PCNA, was significantly correlated with survival. In multivariate analysis, the only immunohistochemical parameter able to influence overall survival was p16, confirming the hypothesis that the RB-p16 tumour suppressor pathway is inactivated in most lung cancer samples. Finally, the group of patients with NSCLC who were negative for both p21 and p16 had a significantly shorter overall survival.

CONCLUSIONS

These results suggest that loss of control of cell cycle checkpoints is a common occurrence in lung cancers, and support the idea that functional cooperation between different cell cycle inhibitor proteins constitutes another level of regulation in cell growth control and tumour suppression.

Efficient Down-Regulation of Cyclin A-Associated Activity and Expression in Suspended Primary Keratinocytes Requires p21Cip1

When suspended in methylcellulose, primary mouse keratinocytes cease proliferation and differentiate. Suspension also reduces the activity of the cyclin-dependent kinase cdk2, an important cell cycle regulatory enzyme. To determine how suspension modulates these events, we examined its effects on wild-type keratinocytes and keratinocytes nullizygous for the cdk2 inhibitor p21Cip1. After suspension of cycling cells, amounts of cyclin A (a cdk2 partner), cyclin A mRNA, and cyclin A-associated activity decreased much more rapidly in the presence than in the absence of p21Cip1. Neither suspension nor p21Cip1 status affected the stability of cyclin A mRNA. Loss of p21Cip1 reduced the capacity of suspended cells to growth arrest, differentiate, and accumulate p27Kip1 (a second cdk2 inhibitor) and affected the composition of E2F DNA binding complexes. Cyclin A-cdk2 complexes in suspended p21+/+ cells contained p21Cip1 or p27Kip1, whereas most of the cyclin A-cdk2 complexes in p21−/− cells lacked p27Kip1. Ectopic expression of p21Cip1 allowed p21−/− keratinocytes to efficiently down-regulate cyclin A and differentiate when placed in suspension. These findings show that p21Cip1 mediates the effects of suspension on numerous processes in primary keratinocytes including cdk2 activity, cyclin A expression, cell cycle progression, and differentiation.

Adrenocortical adenoma and carcinoma: histopathological and molecular comparative analysis

We compared histomorphological features and molecular expression profiles of adrenocortical adenomas (ACAd) and carcinomas (ACCa). A critical histopathological review (mean, 11 slides per patient) was conducted of 37 ACAd and 67 ACCa. Paraffin-embedded tissue cores of ACAd (n = 33) and ACCa (n = 38) were arrayed in triplicate on tissue microarrays. Expression profiles of p53, mdm-2, p21, Bcl-2, cyclin D1, p27, and Ki-67 were investigated by immunohistochemistry and correlated with histopathology and patient outcome using standard statistical methodology. Median follow-up period was 5 years. Tumor necrosis, atypical mitoses, and >1 mitosis per 50 high-power fields were factors that were highly specific for ACCa (P <.001). Number (0 to 4) of unfavorable markers [Ki-67 (+), p21 (+), p27 (+), mdm-2(-)] expressed was significantly associated with mitotic activity and morphologic index (i.e., number of adverse morphologic features) and highly predictive of malignancy (P <.001). Ki-67 overexpression occurred in 0 ACAd and 36% ACCa (P <.001) and was significantly associated with mitotic rate and unfavorable morphologic index (P <.001). Tumor necrosis, atypical mitoses, >5 mitoses per 50 high-power fields, sinusoidal invasion, histologic index of >5, and presence of more than two unfavorable molecular markers were associated significantly with metastasis in ACCa. Well-established histopathologic criteria and Ki-67 can specifically distinguish ACCAd from ACCa. Tumor cell proliferation (Ki-67) correlates with mitotic activity and morphologic index. Tumor morphology is a better predictor of metastatic risk in ACCa than current immunohistochemistry-detected cell cycle regulatory and proliferation-associated proteins.

Prognostic molecular markers for planning adjuvant chemotherapy trials in Dukes' B colorectal cancer patients: how much evidence is enough?

The benefit of postoperative adjuvant chemotherapy in patients with Dukes' B colorectal cancer is still uncertain and its routine use is not recommended. Prognostic biomarkers may be useful for identifying high-risk patients with resected, node-negative disease, and this stratification may represent an innovative strategy for designing adjuvant chemotherapy trials. Featured prognostic molecular markers can be divided into the following categories: cell proliferation indices (Ki-67, Mib-1, proliferating cell nuclear antigen); oncogenes/tumor suppressor genes [p53, K-ras, Deleted in Colorectal Cancer (DCC), Bcl-2, c-erbB2]; DNA repair (microsatellite instability); markers of angiogenesis (vascular count, vascular endothelial growth factor); markers of invasion/metastasis (plasminogen-related molecules, matrix metalloproteinases); and biochemical markers (thymidylate synthase). Studies that have investigated their prognostic role in Dukes' B colorectal cancer patients are reviewed here. Current data do not provide sufficient evidence for the incorporation of available prognostic biomarkers into clinical practice. However, a biomarker-based approach could be an effective strategy for improving results of postoperative adjuvant treatments in high-risk Dukes' B colorectal cancer patients. Markers of altered DCC function have shown promising prognostic role and sufficient prevalence in retrospective investigations and they deserve further assessment in prospective studies.

[Clinical, pathological and molecular prognostic factors in colorectal carcinomas]

Various aspects of the progression and prognosis of colorectal carcinoma have been investigated in numerous publications during recent years. An exact macroscopic and microscopic examination is still of basic importance but different factors of the molecular pathogenesis of colorectal carcinoma could be described by immunohistochemistry and molecular biology. Furthermore, they have been evaluated regarding their importance for the course of disease and prognosis and in particular, the different pathways of carcinogenesis and microsatellite instability were included. The detection of micrometastasis was investigated applying mostly molecular genetic methods. Numerous oncogenes, tumor suppressor genes and regulators of the cell cycle, markers of proliferation and apoptosis, cell adhesion antigens and angiogenetic factors were characterized with regard to their prognostic potential. In the future, so-called response predictors will presumably gain a certain relevance in the context of neoadjuvant (radiotherapy) chemotherapy. The present review summarizes these results and discusses the future clinical relevance.

Parathyroid neoplasms: clinical, histopathological, and tissue microarray-based molecular analysis

We studied 45 patients with typical and 8 with atypical parathyroid adenomas as well as 20 with parathyroid carcinomas. Clinical, pathological, and molecular analyses were conducted on all adenomas. Clinical data were analyzed for 20, histopathologic slides for 16, and tissue specimens for 8 patients with carcinoma. Molecular expression profiles were investigated by immunohistochemistry (IHC) for Ki-67, p53, mdm2, p21, Bcl-2, cyclin D1, and p27 on paraffin-embedded tissues arrayed on tissue microarrays. Trabecular growth and vascular, capsular, and soft-tissue invasion were characteristic of parathyroid carcinomas but not of typical adenomas. No adenomas recurred. Seventy-four percent of carcinomas recurred, most in the neck. Seventy-nine percent of patients with such illness died of disease after an indolent, multiply recurrent course responsive to repeated resections; the 5-year survival rate was 50%. High Ki-67 proliferative index was seen in 2% of adenomas and 25% of carcinomas, whereas p27 expression was present in 80% of adenomas and 18% of carcinomas. The molecular phenotype, p27(+)Bcl-2(+)Ki-67(-)mdm2(+), was observed in 76%, 29%, and 0% of typical and atypical adenomas and carcinomas, respectively. The complexity of molecular phenotypes increased with tumor aggressiveness. Parathyroid carcinoma is an aggressive disease with a propensity for multiple recurrences. It is characterized by capsular, vascular, and soft-tissue invasion. Recurrence portends poor outcome. Molecular markers, Ki-67 and p27, may distinguish parathyroid carcinoma from adenoma. The molecular phenotype, p27(+)Bcl-2(+)Ki-67(-)mdm2(+), appears to be unique to nonmalignant parathyroid tumors, and multimarker phenotypes are more complex in carcinomas.

Loss of the cell cycle inhibitors p21(Cip1) and p27(Kip1) enhances tumorigenesis in knockout mouse models

Events that contribute to tumor formation include mutations in the ras gene and loss or inactivation of cell cycle inhibitors such as p21(Cip1) and p27(Kip1). In our previous publication, we showed that mice expressing the MMTV/v-Ha-ras transgene developed tumors earlier and at higher multiplicities in the absence than in the presence of p21(Cip1). To further evaluate the combinatorial role of genetic alterations and loss of cell cycle inhibitors in tumorigenesis, we performed two companion studies. In the first study, wild type and p21(Cip1)-null mice were exposed to the chemical carcinogen, urethane. Similar to its effects in v-Ha-ras mice, loss of p21(Cip1) accelerated tumor onset and increased tumor multiplicity in urethane-treated mice. Lung tumors were the predominant tumor type in urethane-treated mice regardless of p21(Cip1) status. In the second study, tumor formation was monitored in v-Ha-ras mice expressing or lacking p27(Kip1). Unlike p21(Cip1), the absence of p27(Kip1) had no effect on the timing or multiplicity of tumor formation, which was largely restricted to mammary and salivary glands. However, once tumors appeared, they grew faster in p27(Kip1)-null mice than in p27(Kip1)-wild type mice. Increases in growth rate were particularly striking for salivary tumors in ras/p27(-/-) mice. Loss of p21(Cip1), on the other hand, had no effect on tumor growth rate in v-Ha-ras mice. Collectively, our data suggest that p21(Cip1) suppresses tumor formation elicited by multiple agents and that p21(Cip1) and p27(Kip1) suppress tumor formation in different ways.

Prognostic significance of p21 and p27 protein, apoptosis, clinical and histologic factors in rectal cancer without lymph node metastases

The aim of this study was to evaluate the prognostic role of clinical and histopathologic factors, cell-cycle regulator proteins (p21(Waf1/Cip1), p27(Kip1)), and apoptotic index in lymph node-negative rectal cancer. Formalin-fixed, paraffin-embedded tissue samples of 97 rectal carcinomas (UICC stages I and II) resected curatively within five years were used. Immunohistochemical analysis of protein expression was performed by monoclonal antibodies: p21 (clone SX118), p27 (clone SX53G8). Apoptosis was assessed by the TUNEL method. Clinical, surgical, histopathologic, and follow-up data were prospectively recorded in a computerized registry. To assess prognostic significance (end points: metachronous distant metastases, 5-year disease-free and overall survival), statistics included univariate and multivariate analysis (p < 0.05 statistically significant). Of the 97 rectal carcinomas without lymph node metastases, 46.4% (45/97) were p21-positive, 49.5% were p27-positive (48/97), whereas 27.8% (27/97) showed a high apoptotic index. Within a median follow-up of 54 months, 4 patients developed local recurrence (4.1%). Distant metastases occurred in 12 patients (12.4%). Univariate analysis showed that gender, UICC stage, p21 and p27 were significantly associated with the incidence of distant metastases (p < 0.05). UICC stage and p21 were the only factors to be significantly related to 5-year disease-free survival by univariate analysis (p < 0.05). Only UICC stage was significantly related to 5-year overall survival (p < 0.05). The apoptotic index was correlated neither to recurrence nor to survival (p > 0.05). Multivariate analysis demonstrated that gender, UICC stage and p21 were independently related to the incidence of distant metastases; however, UICC stage was the only independent factor predictive of 5-year disease-free survival and overall survival (p < 0.05).

Prognostic significance of calcium-binding protein S100A4 in colorectal cancer

BACKGROUND & AIMS

Prognostication in colon cancer almost exclusively still rests on the tumor stage. Furthermore, tumor-derived markers to improve discrimination of low- and high-risk subtypes generally are not in use. S100A4 has been reported to be associated with invasion and metastasis; however, no data are available on its prognostic value in colorectal carcinoma. Therefore, we investigated the prognostic significance of immunohistochemical S100A4 expression in colorectal carcinoma compared with clinicopathologic parameters and expression of cell-cycle markers p16, p21, p27, p53, Ki-67, and RB.

METHODS

Archival tissue from 709 patients with colorectal cancer were retrieved, applied in tissue array technology, and investigated immunohistochemically. Univariate and multivariate survival analyses were carried out on all investigated parameters.

RESULTS

Sixteen percent of cases showed high; 31%, low; and 53%, no S100A4 expression. In Kaplan-Meier analysis, S100A4 positively stained cases showed a significantly decreased survival time compared with negatively stained cases (P < 0.0001). In multivariate regression analysis, S100A4 expression emerged as a highly significant independent parameter (P < 0.001) with the highest relative-risk factor among other covariates. Nodal status (pN) lost its prognostic value if S100A4 was added to the model. High S100A4 expression was associated with tumor stage pT3/4, secondary metastasis, women, p16, and RB expression.

CONCLUSIONS

S100A4 expression represents a highly significant prognostic marker in colorectal carcinoma, which is able to identify a subset of patients at high risk. In this respect, it is superior to established prognostic markers such as nodal status, pT stage, and p53 expression.

Prevalence and prognostic role of microsatellite instability in patients with rectal carcinoma

BACKGROUND

Association between microsatellite instability (MSI) and favorable postoperative survival in patients with colorectal cancer receiving adjuvant chemotherapy has been indicated. To evaluate whether an analogous positive prognostic role of MSI could be present in rectal carcinoma (RC; most RC patients receive adjuvant radiotherapy), PCR-based microsatellite analysis of archival RCs and statistical correlation with clinico-pathological parameters were performed.

PATIENTS AND METHODS

DNA from paraffin-embedded paired samples of tumors and corresponding normal tissue from 91 RC patients was analyzed for MSI using five microsatellite markers (tumors were classified as MSI(+) when two or more markers were unstable).

RESULTS

Seventeen (19%) RC patients exhibited a MSI(+) phenotype. Prevalence of instability was found in patients with earlier RC onset (28% in cases with diagnosis age < or =55 years versus 15% in cases >55 years), whereas similar MSI frequencies were observed in patients with different disease stage or receiving different adjuvant therapies. While MSI was detected in seven (64%) of 11 familial patients, a remarkably lower MSI incidence was observed in sporadic cases (10/80; 12.5%). A significant association with better disease-free survival (DFS) and overall survival (OS) was found for MSI(+) patients (median DFS/OS, 30/32 months) in comparison to MSI(-) ones (median DFS/OS, 18/21 months) (P <0.001).

CONCLUSIONS

MSI was demonstrated to be a strong molecular prognostic marker in rectal carcinoma, independent of the administered treatment (radiotherapy, chemotherapy or both).

Oncogenic functions of tumour suppressor p21(Waf1/Cip1/Sdi1): association with cell senescence and tumour-promoting activities of stromal fibroblasts

p21(Waf1/Cip1/Sdi1) is best known as a broad-specificity inhibitor of cyclin/cyclin-dependent kinase complexes, but p21 also interacts with many other regulators of transcription or signal transduction. p21 induction, which is mediated by p53 and by p53-independent mechanisms, is essential for the onset of cell cycle arrest in damage response and cell senescence. The effects of p21 knockout in mice and its expression patterns in human cancer are consistent with a role for p21 as both a tumour suppressor and an oncogene. Several functions of p21 are likely to promote carcinogenesis and tumour progression. These include endoreduplication and abnormal mitosis that develop in tumour cells after release from p21-induced growth arrest, the ability of p21 to inhibit apoptosis through several different mechanisms, and its ability to stimulate transcription of secreted factors with mitogenic and anti-apoptotic activities. The latter effects of p21 show close resemblance to paracrine activities of senescent cells and to tumour-promoting functions of stromal fibroblasts. Therapeutic strategies targeting the oncogenic consequences of p21 expression may provide a new approach to chemoprevention and treatment of cancer.

Analysis of key cell-cycle checkpoint proteins in colorectal tumours

Aberrations in the components of cell-cycle checkpoints are a common feature of many tumours and several have been shown to have prognostic significance in colorectal cancer. In this study, seven components of cell-cycle control [cyclin D1, retinoblastoma (pRb), p21, p27, p16, p53, and proliferating cell nuclear antigen (PCNA)] were examined in a large series of well-characterized colorectal adenocarcinomas using immunohistochemistry to ascertain co-regulation and influence on survival. The majority (92%) of the tumours had abnormal staining of > or =2 cell-cycle control factors. Expression of cyclin D1 protein was correlated with both p21 (p<0.001) and p27 (p=0.033), suggesting co-regulation of these proteins in colorectal tumours. Only cyclin D1 (p=0.048) and p53 (p=0.025) were directly associated with PCNA levels, suggesting a more important role in the proliferative capacity of tumour cells. Significant associations between cell cycle-related proteins and clinicopathological data were observed: cyclin D1 and p53 proteins were correlated with patient age (p=0.042 and p<0.001, respectively) and p53 (p=0.01) and p21 (p=0.024) proteins were associated with tumour site. Expression of cyclin D1 protein was the only protein examined that was related to improved outcome in these patients (p=0.0266), but it was not an independent predictor of survival. These results suggest that loss of control of cell-cycle checkpoints is a common occurrence in colorectal tumours and may be an important therapeutic target.

Prognostic role of p21WAF1 expression in areca quid chewing and smoking-associated oral squamous cell carcinoma in Taiwan

BACKGROUND

Alterations in p21WAF1 protein expression have been observed in a wide variety of human cancers by immunohistochemistry, and both decreased and increased levels of p21WAF1 protein expression have been shown to correlate with poor prognosis.

METHOD

To examine the relation between p21WAF1 protein expression and prognosis in oral squamous cell carcinomas (SCCs), we performed an immunohistochemical study with antip21WAF1 antibody on 43 oral SCCs. Immunostaining results were then correlated with p53 protein levels, clinicopathological parameters of the tumors and overall patient survival.

RESULTS

Of the 43 patients, 31 (72%) had tumors with positive p21WAF1 nuclear staining and 27 (63%) had tumors with p53 nuclear staining. There was no significant correlation between p21WAF1 and p53 protein expressions and both mutant p53-containing oral SCCs overexpressed p21WAF1 protein. In addition, no significant correlation was found between the p21WAF1 expression and the patients' age, sex, oral habit, cancer location, or primary tumor TNM status at the time of initial presentation. The Kaplan-Meier analysis showed a significant correlation between p21WAF1 protein overexpression and poor patient overall survival (P = 0.049). When p53 and p21WAF1 were evaluated together, the 5-year overall survival was lowest in p53(+)-p21WAF1(+) patients and highest in p53(-)-p21WAF1(-) patients (P = 0.057).

CONCLUSION

Combined evaluation of p21WAF1 and p53 expressions may be useful in estimating the prognosis of patients with oral SCCs in Taiwan.

Methylation of the hMLH1, p16, and MDR1 genes in colorectal carcinoma: associations with clinicopathological features

The methylation status of seven cancer-related genes was investigated in a series of 58 colorectal cancers, 18 of which showed the microsatellite instability (MSI+) phenotype. Methylation of the hMLH1, p16 and MDR1 genes was found in 23, 29 and 28% of tumors, respectively. None of the tumors showed methylation of the TS, ATM, PARP or p21 genes. Methylation of the hMLH1, p16 and MDR1 genes was more frequent and more concordant in MSI+ compared to MSI- tumors (P<0.001) and was also strongly associated with poor histological differentiation (P<0.001). There were trends for associations between methylation at one or more of these loci and proximal tumor location, advanced Dukes' stage and the presence of wild-type p53 (P=0.06 for each).

Aberrant Expression of Cyclin D1 Is Associated with Poor Prognosis in Early Stage Cervical Cancer of the Uterus

OBJECTIVE

Many investigators have studied the expression of G1 phase regulatory protein in uterine cervical cancer. However, it is unclear which step of the genetic expression participates in cyclin D1 expression and what its prognostic meaning is. The aims of this study were to evaluate the regulatory level of cyclin D1 expression and the relationship between the expression of cyclin D1 and its inhibitor, p21WAF1/CIP1, and to evaluate their impact on the prognosis of early stage cervical cancer.

METHODS

The presence of cyclin D1 mRNA was studied using Northern blot in 6 normal cervices and 7 invasive cervical cancer specimens. Western blot was used to detect the cyclin D1 protein in 8 normal cervices and 8 invasive cancer specimens. Thirty-two cases of FIGO stage Ib-IIa cervical cancers (28 squamous cell carcinomas, 3 adenocarcinomas, 1 adenosquamous cell carcinoma), 31 cases of cervical intraepithelial neoplasia 3 (CIN 3), and 28 normal cervices were stained for cyclin D1 and p21(WAF1/CIP1) using monoclonal antibody. Statistical analysis was performed to assess the differences in expression and their prognostic significance. RESULTS. Cyclin D1 mRNA was found to be underexpressed in cervical cancer. Western blot also revealed underexpression of cyclin D1 protein in cervical cancer compared to normal controls. Positive immunohistochemical staining of cyclin D1 was noted in 28/28 (100%) of the normal controls, 1/31 (3%) cases of CIN 3, and 9/32 (28%) cases of invasive cancer. The number of positively stained specimens was lower than that of normal controls in CIN 3 and cervical cancer specimens (P = 0.005). Fifteen of 28 (54%) normal controls, 15/31 cases (48%) of CIN 3, and 27/32 cases (84%) of invasive cancer were proved positive for p21WAF1/CIP1 immunohistochemistry. p21WAF1/CIP1 was more highly expressed in cervical cancer than in that of either normal controls or CIN specimens (P = 0.001). Positive immunostaining of cyclin D1 and p21WAF1/CIP1 was not related to high-risk factors (pelvic lymph node metastasis, deep cervical stromal invasion, parametrial invasion, large tumor size, and unusual histologic type) and human papilloma virus infection. Positive cyclin D1 immunostaining was associated with decreased disease-free survival and a lower overall survival (P = 0.0175 and 0.0189, respectively). On multivariate analysis, positive cyclin D1 expression was a significant prognostic variable for recurrence (P = 0.0004).

CONCLUSION

Underexpression of cyclin D1 was regulated at the level of transcription in cervical cancer. Although cyclin D1 was underexpressed in cervical neoplasias, it was more frequently expressed in malignant lesions. p21WAF1/CIP1 was more highly expressed in cervical cancers than in either normal cervices or CIN 3 specimens. Unfavorable prognoses were associated with cyclin D1 expression, and not with the expression of its inhibitor, p21WAF1/CIP1.We conclude that immunohistochemical assessment of cyclin D1 can be a useful molecular marker for predicting prognosis in early stage cervical cancer of the uterus.