Expression of p27 and p53 in cervical squamous cell carcinoma patients treated with radiotherapy alone: radiotherapeutic effect and prognosis

Olive: A Potential Suppressor for Cervical Cancer by Upregulation of P21

Background Cervical cancer is the second deadliest for women between the ages of 20 and 39 years. Even with prevention tactics for screening, incident rates and mortality of cervical cancer remain high. Olive has been shown to have many beneficial effects in humans concerning cardiovascular disease and inflammation. Despite these promising benefits, little is known about its effect on cervical cancer. This study examined the effects and mechanism of effects of olive extract (OE) on the HeLa cervical cancer cell line. Methodology We utilized clonogenic survival assay, quick cell proliferation assay, and caspase-3 activity to investigate the effect of OE on the proliferation and apoptosis of the cervical cancer cell line HeLa. To investigate the mechanisms behind these findings, Reverse transcription polymerase chain reaction and immunohistochemistry were performed. Results OE inhibited the growth and proliferation of HeLa cells. In comparison to the control, the percentage of colonies, as well as the optical density of the cervical cancer cells, was found to be decreased. In addition, the relative activity of caspase-3, a marker for apoptosis, was increased after treatment with OE. The anti-proliferative effect of OE on HeLa cells correlated with the increase of an anti-proliferative molecule p21. However, the pro-apoptotic effect of OE was not correlated with the change in major pro-apoptotic or anti-apoptotic molecules examined in this study. Conclusions Our study suggests that OE inhibits the growth of HeLa cervical cancer cells by upregulation of p21. Further investigation of the effects of OE on cervical cancer and other cancers is warranted by these results.

Farnesoid X receptor functions in cervical cancer via the p14ARF-mouse double minute 2-p53 pathway

BACKGROUND

Cervical cancer is the second most common cancer among women living in developing countries. Farnesoid X receptor (FXR) is a member of the nuclear receptor family, which regulates the development and proliferation of cancer. However, the role of and molecular mechanism by which FXR acts in cervical cancer are still unknown.

METHODS AND RESULTS

The relationship between FXR and the proliferation of cervical cancer cell lines was detected by MTT and colony formation assays. Immunohistochemistry was used to detect the expression of FXR in cervical cancer tissue slides. Western blotting was used to detect the expression of p14^ARF, mouse double minute 2 (MDM2) and p53 when FXR was overexpressed or siRNA was applied. Western blotting was used to detect the expression of MDM2 and p53 when pifithrin-α (PFT-α) was applied. FXR activation inhibited the proliferation of cervical cancer cell lines. FXR was significantly decreased in cervical squamous cell carcinoma, which was correlated with TNM stage, but not with metastasis. Overexpression of FXR activated the p14^ARF-MDM2-p53 pathway. As a p53 inhibitor, PFT-α increased MDM2 in Lenti-vector cells, but had no effect on MDM2 in Lenti-FXR cells.

CONCLUSIONS

FXR inhibits cervical cancer by upregulating the p14^ARF-MDM2-p53 pathway. Activation of FXR may be a potential strategy for the treatment of cervical cancer.

Potential use of kiwifruit extract for treatment of melanoma

Skin cancers are the most common cancers in the world and among the different types of skin cancers, melanoma is the deadliest and incidence is rising. Previous studies have shown promising in vitro and human evidence of kiwifruit exhibiting anti-cancer effects. This study was designed to investigate if kiwifruit extract (KE) has any effect on CRL-11147 melanoma cancer cells and to investigate the possible mechanisms behind the results. The effects of KE on CRL-11147 melanoma cell survival, proliferation, and apoptosis was investigated using clonogenic survival assay, cell proliferation, and caspase-3 activity kits. Potential anti-tumor molecular mechanisms were elucidated using RT-PCR and IHC. Addition of KE decreased CRL-11147 cell colonies percentages indicated by a decreased optical density value of cancer cells when compared to control. Furthermore, treatment with KE increased relative caspase-3 activity in cancer cells, which indicated increased apoptosis of cancer cells. The anti-proliferative effect of KE on cancer cells corresponded with decreased expression of the pro-proliferative molecule Cyclin E and CDK4, while increased expression of the pro-apoptotic molecule TRAILR1 corresponded with the pro-apoptotic effect. KE decreases CRL-11147 melanoma cell growth via downregulation of Cyclin E and CDK4 and upregulation in TRAILR1. Our study suggests a potential use for KE in treatment of melanoma.

Validation of p27KIP1 expression levels as a candidate predictive biomarker of response to rapalogs in patient-derived breast tumor xenografts

Blockade of mammalian target of rapamycin (mTOR) is a promising area in breast cancer therapy. However, in clinical trials, objective response rate with mTOR inhibitor monotherapy in breast cancer was modest. Biomarker studies designed to identify the responders of rapalogs are of increasing interest. We validated p27KIP1 expression levels as a candidate predictive biomarker of response to rapalogs. We also analyzed the correlation between rapamycin activity and p27KIP1 expression in the primary breast cancer cells and the patient-derived breast tumor xenograft models. The cells isolated from the breast tumor tissues expressing high levels of p27KIP1 were sensitive to rapamycin, whereas the cells from the tissues expressing low levels of p27KIP1 exhibited resistance to rapamycin. The correlation between p27KIP1 expression and rapamycin antitumor activity was also observed in the patient-derived breast tumor xenograft models. Moreover, we also found rapamycin significantly decreased phosphorylated p70S6K1 and phosphorylated 4EBP1 in both samples. It seemed that the different sensitivity of tumor cells to rapamycin did not owe to its different potency against mTOR activity. We further propose p27KIP1 expression level may be also a candidate predictive biomarker of rapalogs for breast cancer therapy, which requires additional clinical validation.

Expression of p27Kip1 and E-cadherin in Head and Neck Squamous Cell Carcinoma of Indonesian Patients

Cancer cells exhibit characteristic damage of DNA and its expression. The expression of the tumor suppressors E-cadherin and p27^Kip1 has been tested on 57 head and neck squamous cell carcinomas (HNSCC) of Indonesian subjects. HNSCC tumor samples including both primary and (unrelated) nodal cases were obtained from the archives of Indonesian hospitals, in accordance with acknowledged ethical requirements. Only modest correlation was found between reduced expression of E-cadherin or p27^Kip1 with increased malignancy of primary and nodal growth. The observed strong correlation regardless of malignancy between the expressed levels of E-cadherin and p27^Kip1 suggests that also in combination these would not help to better predict the outcome of HNSCC.

A comparative analysis of clinical and molecular factors with the stage of cervical cancer in a Brazilian cohort

Cell cycle protein expression plays an important role in the pathophysiology of cervical cancer. However, few studies have attempted to correlate the use of these biomarkers with the clinical progression of the tumor.

Correlation of p53 and Ki-67 (MIB-1) expressions with clinicopathological features and prognosis of early stage cervical squamous cell carcinomas

AIM

To evaluate the prognostic significance of the expression of p53 and Ki-67, and their correlation with various clinicopathological factors in patients with squamous cell carcinoma of the uterine cervix treated by radical hysterectomy.

METHODS

Two hundred and thirty five patients diagnosed between 1987 and 2004 were investigated for p53 and Ki-67 expression by immunohistochemistry. The relationship of these proteins and other potential prognostic factors with recurrence-free survival (RFS) was evaluated.

RESULTS

The mean age of the patients was 43.9 years (range, 27-68). There were 28 cases with stage IA2 (11.9%) and 207 cases with stage IB1 (88.1%). The overall 5-year RFS was 91.1% (95% confidence interval [CI] 86.0, 94.4). p53 and Ki-67 expressions were seen in 33.6% and 81.3% of cases, respectively. p53 expression was significantly associated only with parametrial or marginal involvement (P = 0.005), while Ki-67 expression significantly correlated only with larger tumor (P = 0.011) and parametrial or marginal involvement (P = 0.024). There was significant correlation between the expression of p53 and Ki-67 (P = 0.021). In multivariate analysis, Ki-67 expression (hazard ratio for >or=3rd vs 1st tertile [>or=30% vs <20% expression] = 16.0, 95%CI 2.1-124.5; P = 0.0015) appeared to be an independent prognostic factor for RFS, while no prognostic significance of p53 expression was found.

CONCLUSION

Ki-67 expression is an independent prognostic parameter for RFS in patients with early stage squamous cell carcinoma of the uterine cervix. Ki-67 expression at or above the cut-off point of 30.0% had significantly poorer RFS.

Comparison of the radiobiological effect of carbon ion beam therapy and conventional radiation therapy on cervical cancer

Little clinical evidence has been provided to show the minimization of radiation resistance of tumors using high linear energy transfer radiation. We therefore investigated the radiobiological and molecular pathological aspects of carbon beam therapy. A total of 27 patients with squamous cell carcinoma (SCC) of the cervix were treated using a carbon beam and 50 control patients with SCC of the cervix using a photon beam. The expression of Ki-67, p53, and p27 proteins before radiotherapy and 5 and 15 days after therapy initiation were investigated using immunohistochemistry. Similar changes were observed in Ki-67 labeling index (LI) and p53 LI during carbon and photon beam therapies. However, for carbon beam therapy, the mean p27 LI significantly decreased from 25.2% before treatment to 18.6% on the 5th day after treatment initiation, followed by a significant increase to 36.1% on the 15th day. In contrast, for photon beam therapy, the p27 LI consistently decreased from the initial 19.9% to 13.7% on the 15th day. Histological effects were observably stronger under carbon than photon beam therapy, though no statistically significant difference was observed (p = 0.07 on the 5th day and p = 0.10 on the 15th day). The changes in p27 LI under carbon beam therapy were significantly different from those under photon beam therapy, which suggests important molecular differences in the radio-biological response between therapies. Further investigation is required to elucidate the clinical relevance of these putative changes and optimize the relative biological effectiveness of carbon beam to X-ray.

Expression of p16INK4a and cervical infection with high-risk human papillomavirus are not related to p53 activity in cervical intraepithelial neoplasia

The objective of the study was to investigate the expression of p53 and p16INK4a in cervical intraepithelial neoplasia (CIN) and their relation with disease severity and high-risk human papillomavirus (HR-HPV) status. A series of 125 women with previous positive Pap smear were selected for this cross-sectional study. All patients underwent gynecological examination, including colposcopy. Specimens for Pap smears, Hybrid Capture 2 (HC2) test, and pathologic analysis were obtained. After evaluation of CIN grade, immunohistochemical detection of proteins p53 and p16INK4a was performed on paraffin-embedded sections. The extent of immunoexpression of both proteins was analyzed in relation to CIN grade and HR-HPV status. CIN was graded as 1 in 21, 2 in 17, and 3 in 87 specimens. p16INK4a positivity (at least 5% of epithelial cells stained) was found in 99 of 125 cases (79.2%) and was significantly higher in high-grade lesions as compared to low-grade CIN (P< 0.001). The expression of p53 did not differ across histologic strata. Protein expression neither of p16INK4a nor of p53 correlated with HR-HPV status. Expression of p16INK4a was not related with that of p53. Our study gives further support to previous findings of strong association of p16INK4a immunostaining with severity of epithelial atypia, but this protein may not be considered a predictor of HR-HPV status determined with HC2. By contrast, immunoexpression of p53 was related neither to CIN grade nor to HR-HPV status.

The Cdk inhibitor p27 in human cancer: prognostic potential and relevance to anticancer therapy

The cyclin-dependent kinase (Cdk) inhibitor p27 (also known as KIP1) regulates cell proliferation, cell motility and apoptosis. Interestingly, the protein can exert both positive and negative functions on these processes. Diverse post-translational modifications determine the physiological role of p27. Phosphorylation regulates p27 binding to and inhibition of cyclin-Cdk complexes, its localization and its ubiquitin-mediated proteolysis. In cancers, p27 is inactivated through impaired synthesis, accelerated degradation and by mislocalization. Moreover, studies in several tumour types indicate that p27 expression levels have both prognostic and therapeutic implications.

p27kip1 deficiency impairs G2/M arrest in response to DNA damage, leading to an increase in genetic instability

p27(kip1) is a cyclin-dependent kinase inhibitor and a tumor suppressor. In some tumors, p27 suppresses tumor growth by inhibition of cell proliferation. However, this is not universally observed, implying additional mechanisms of tumor suppression by p27. p27-deficient mice are particularly susceptibility to genotoxin-induced tumors, suggesting a role for p27 in the DNA damage response. To test this hypothesis, we measured genotoxin-induced mutations and chromosome damage in p27-deficient mice. Both p27(+/-) and p27(-/-) mice displayed a higher N-ethyl-N-nitrosourea-induced mutation frequency in the colon than p27(+/+) littermates. Furthermore, cells from irradiated p27-deficient mice exhibited a higher number of chromatid breaks and showed modestly increased micronucleus formation compared to cells from wild-type littermates. To determine if this mutator phenotype was related to the cell cycle-inhibitory function of p27, we measured cell cycle arrest in response to DNA damage. Both normal and tumor cells from p27-deficient mice showed impaired G(2)/M arrest following low doses of ionizing radiation. Thus, p27 may inhibit tumor development through two mechanisms. The first is by reducing the proliferation of cells that have already sustained an oncogenic lesion. The second is by transient inhibition of cell cycle progression following genotoxic insult, thereby minimizing chromosome damage and fixation of mutations.

Phenotypic features with p53 alterations related to human papillomavirus and prognostic evaluation in cervical cancer

Cervical cancer is one of the most common tumor affecting women worldwide. Human papillomavirus (HPV) was found to have a causal relationship with cervical cancer and its precursors. The interaction between HPV E6 protein and p53 was identified in in vitro studies. The aim of the study was to evaluate the prevalence of p53 alterations related to HPV infection and the prognostic significance of p53 alterations in cervical cancer. Studies were identified by a MEDLINE search, and all relevant articles were retrieved from 1991 to March 2004. The prevalence of p53 mutations is a rare event in cervical cancer. The correlation between p53 mutations and HPV or prognosis is controversial. Loss of heterozygosity (LOH) of p53 is more commonly found in cervical cancer and is related with the prognosis of this disease. There is no significant correlation between p53 polymorphism and development of cervical cancer. The p53 mutations were not commonly found in cervical cancer. LOH of p53 may contribute to the progression of this malignancy. p53 polymorphism failed to be an independent prognostic factor in predicting the outcome of patients with cervical cancer. Further, epidemiologic surveys should be undertaken in larger populations and in different geographical regions.

Microvessel density and p53 in detecting cervical cancer by FDG PET in cases of suspected recurrence

PURPOSE

Cervical cancer is the second most frequently diagnosed cancer in women worldwide. About one-third of patients experience recurrent disease. A better chance of survival might be achieved by the early detection of recurrent cervical cancer. [(18)F]fluoro-2-deoxy-D-glucose (FDG) PET could be a promising imaging modality for this purpose, given that FDG PET has high diagnostic efficacy. Ideally, pre-selection of patients should be performed before considering FDG PET. The purpose of this study was to investigate parameters of primary cervical cancer associated with recurrence as a basis for pre-selection of patients in whom FDG PET should be performed.

METHODS

Thirty-eight cervical cancer patients, clinically suspected of having recurrent disease, underwent FDG PET. Tissue from primary tumours and nine histologically confirmed metastases was analysed for biomarkers possibly related to glucose metabolism and prognosis (vascular endothelial growth factor, CD31 for microvessel density, glucose transporter-1, hexokinases I, II and III, Ki67, p53, hypoxia-inducible factor 1alpha, and degree of infiltration by lymphocytes and macrophages).

RESULTS

Based on clinical outcome, sensitivity and specificity of FDG PET were 96% and 100%, respectively. Cox regression revealed microvessel density and p53 (tumour suppressor protein) to be the two most important biomarkers for prediction of recurrence (hazard ratios 2.54 and 2.28, respectively). By combining these two biomarkers in a parallel test, sensitivity and specificity in predicting recurrence were 87% and 71%, respectively. Leave-one-out cross-validation demonstrated predictive validity of a model based on microvessel density and p53.

CONCLUSION

In this first study of its kind, we have demonstrated that microvessel density and p53 profiles could be important in pre-selecting cervical cancer patients for detection of recurrence by FDG PET.

Aberrant cell cycle regulation in cervical carcinoma

Carcinoma of the uterine cervix is one of the most common malignancies among women worldwide. Human papillomaviruses (HPV) have been identified as the major etiological factor in cervical carcinogenesis. However, the time lag between HPV infection and the diagnosis of cancer indicates that multiple steps, as well as multiple factors, may be necessary for the development of cervical cancer. The development and progression of cervical carcinoma have been shown to be dependent on various genetic and epigenetic events, especially alterations in the cell cycle checkpoint machinery. In mammalian cells, control of the cell cycle is regulated by the activity of cyclin-dependent kinases (CDKs) and their essential activating coenzymes, the cyclins. Generally, CDKs, cyclins, and CDK inhibitors function within several pathways, including the p16(INK4A)-cyclin D1-CDK4/6-pRb-E2F, p21(WAF1)- p27(KIP1)-cyclinE-CDK2, and p14(ARF)-MDM2-p53 pathways. The results from several studies showed aberrant regulation of several cell cycle proteins, such as cyclin D, cyclin E, p16(INK4A), p21(WAF1), and p27(KIP1), as characteristic features of HPV- infected and HPV E6/E7 oncogene-expressing cervical carcinomas and their precursors. These data suggested further that interactions of viral proteins with host cellular proteins, particularly cell cycle proteins, are involved in the activation or repression of cell cycle progression in cervical carcinogenesis.

Role of the ubiquitin-proteasome pathway in the diagnosis of human diseases

The ubiquitin-proteasome pathway constitutes the major system for nuclear and extralysosomal cytosolic protein degradation in eukaryotic cells. A plethora of cell proteins implicated in the maintenance and regulation of essential cellular processes undergoes processing and functional modification by proteolytic degradation via the ubiquitin-proteasome pathway. Deregulations of the pathway have been shown to contribute to the pathogenesis of several human diseases, such as cancer, neurodegenerative, autoimmune, genetic and metabolic disorders, most of them exhibiting abnormal accumulation and altered composition of components of the pathway that is suitable for diagnostic proceedings. While the ubiquitin-proteasome pathway is currently exploited to develop novel therapeutic strategies, it is less regarded as a diagnostic area. Future research should lead to an improved understanding of the pathophysiology of the ubiquitin-proteasome pathway with the aim of allowing the development of subtle diagnostic strategies.

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.

Cyclooxygenase-2 expression predicts recurrence of cervical dysplasia following loop electrosurgical excision procedure

OBJECTIVE

To evaluate the expression of Cox-2 protein by immunohistochemistry in cervical dysplasias, and to determine any relationship to clinical factors such as degree or recurrence of dysplasia.

METHODS

Immunohistochemical expression of p27 and Cox-2 was initially examined in 62 cervical LEEP specimens, which spanned the histologic spectrum from benign to severe dysplasia. Histology and cytology from colposcopic follow-up exams were reviewed for 1 year after LEEP procedure. Primary outcome variable was recurrent dysplasia, either cytologic or histologic. Statistical analysis utilizing chi-square test for trend and Fisher's Exact tests were performed to determine relative risk of recurrent dysplasia.

RESULTS

A total of 62 LEEP specimens were examined by immunohistochemistry (IHC). This included 18 mild, 19 moderate, and 25 severely dysplastic LEEP specimens. The percentage of tumor cells in each specimen that stained for p27 protein or Cox-2 enzyme was documented. A specimen was considered positive for p27 or Cox-2 if 50% or more of the cells in a specimen were stained: 94% of mild, 89% of moderate, and 44% of severe dysplasias stained positive for p27; 50% of mild, 42% of moderate, and 68% of severe dysplasia specimens stained positive for Cox-2. The average intensity of Cox-2 staining increased with severity of dysplasia-1.6 for mild, 1.8 for moderate, and 2.1 for severe dysplasia. There was a significant increase in both Cox-2 and p27 staining when severely dysplastic specimens were compared to mild and moderate dysplasia (P < 0.001). Of the 35 specimens that stained positive for Cox-2 protein, 59% of these specimens had positive Cox-2 staining that extended to the margins of the LEEP resection specimen. The average length of Cox-2 protein staining beyond the histologic dysplasia was 1.64 mm. Positive margin status for Cox-2 was a significant independent risk factor for persistent and recurrent dysplasia, RR 1.68 95% CI (1.07 < RR < 2.65), P < 0.027.

CONCLUSION

Cox-2 and p27 protein expression could be involved in squamous cervical cancer carcinogenesis. Cox-2 staining is often found outside the dysplastic lesion and this factor is associated with an increased risk of persistent and recurrent dysplasia following LEEP procedure. Should the histologic margin of LEEP resection approach 2.0 mm, follow-up algorithms for these patients should include intensive surveillance to ensure adequate treatment of disease.

p27 deregulation in breast cancer: prognostic significance and implications for therapy

p27 is a key regulator of G1-to-S phase progression. It prevents premature activation of cyclin E-cdk2 in G1 and promotes the assembly and activation of D-type cyclin-cdks. While the p27 gene is rarely mutated in human cancers, the action of p27 is impaired in breast and other human cancers through accelerated p27 proteolysis, sequestration by cyclin D-cdks, and by p27 mislocalization in tumor cell cytoplasm. Reduced p27 protein is strongly associated with high histopathologic tumor grade, reflecting a lack of tumor differentiation. Loss of p27 is also an indicator of poor patient outcome in a majority of breast cancer studies, including node negative disease. The broad application of p27 in the clinical evaluation of breast cancer prognosis will require a consensus on methods of tumor fixation, staining, and scoring. This review will focus on mechanisms of p27 regulation in normal cells and how deregulation of p27 may arise in breast and other human cancers. The prognostic significance of p27 in human breast cancer and the possible therapeutic implications of these findings will also be reviewed.

Mutant p53 protein in the serum of patients with cervical carcinoma: correlation with the level of serum epidermal growth factor receptor and prognostic significance

We have previously reported that the serum level of epidermal growth factor receptor (EGFR) was significantly elevated in 38 cervical carcinoma patients. The levels of mutant p53 protein were determined in the serum of the same cohort (invasive or recurrent carcinoma: 26, carcinoma in situ (CIS): 12) and 18 controls using ELISA. The median serum level for mutant p53 in cervical carcinoma patients (0.11 ng/ml; range, 0-2.66 ng/ml) demonstrated no significant difference compared to that of controls (0.14 ng/ml; range, 0-0.34 ng/ml) (P=0.324). Serum mutant p53 showed positive elevation in 5 patients with invasive or recurrent carcinoma (19%) and 1 with CIS (8%). A significant correlation was found between EGFR and mutant p53 levels (r=0.668; P<0.0001). In invasive or recurrent cervical carcinoma, positive mutant p53 was significantly associated with poor overall survival in both univariate (P=0.035) and multivariate (P=0.046) analysis, while increased level of EGFR did not show prognostic significance (P=0.755). Serum mutant p53 could have potential usefulness as a biological marker of cervical carcinoma for prediction of prognosis and follow-up after treatment.

Role of cell-cycle regulatory proteins in gynecological cancer

Human malignant tumors are characterized by abnormal proliferation resulting from alterations in cell-cycle regulatory mechanisms. This review summarizes the current knowledge about these aberrations in malignant tumors of the ovary, endometrium, cervix uteri, and vulva. The data indicate that analysis of single cell cycle stimulating or inhibiting proteins partly produces unexpected, apparently paradoxical results, and cell-cycle regulatory pathways should be regarded as a whole in order to identify the molecular mechanisms leading to abnormal tumor cell proliferation. For the papillomavirus (HPV)- associated cervical and vulvar carcinomas, the manifold effects of the viral oncogenes E6 and E7 on cell-cycle control are described.

Impact of oxygenation status and patient age on DNA content in cancers of the uterine cervix

PURPOSE

In carcinomas of the uterine cervix, the tumor oxygenation status has been shown to be a prognostic indicator that is independent of treatment modality. In vitro studies suggest gene amplification and polyploidization to be among the major consequences of hypoxia (with or without consecutive reoxygenation) and to be associated with treatment resistance and tumor progression. This study analyzed whether hypoxia alters net DNA content in uterine cervix cancer cells to the extent that it is identifiable by DNA image cytometry.

MATERIALS AND METHODS

In 64 patients with primary cervical cancer, tumor oxygenation was assessed polarographically and correlated with cell DNA content (DNA image cytometry) in areas adjacent to the oxygen microsensor tracks in which oxygenation measurements were made.

RESULTS

No correlation between DNA content (stemline position, Auer classification, and 2c deviation index) and oxygenation status was observed. However, an association between DNA content and patient age and menopausal status was found.

CONCLUSION

Using DNA cytometry, hypoxia-associated genomic changes in uterine cervix cancer cells could not be detected. The impact of tumor hypoxia on the genome may be masked by the effects of alternative mechanisms of genomic instability that can also influence DNA content.

Expression of p27, p21, and p16 protein in early squamous cervical cancer and its relation to prognosis

OBJECTIVE

To examine the prognostic significance of the protein expression of the cyclin-dependent kinase (cdk) inhibitors p27, p21, and p16 in early squamous cervical cancer (SCC).

METHODS

From 221 [corrected] patients who underwent radical hysterectomy and bilateral lymphadenectomy at our institution for stage IB SCC between 1987 and 1993, tissue blocks were available for this study. Immunohistochemistry using monoclonal antibodies against p27, p21, and p16 was used to examine protein expression. Ten patients who underwent hysterectomy for uterine prolaps served as controls.

RESULTS

p21 and p16 expression were increased in SCC and high expression was observed in 20% (44/221) and 43% (94/220) of tumors, respectively. p27 was decreased in SCC and low expression was found in 80% (177/221) of tumors. In univariate analysis all classical clinicopathological parameters were associated with prognosis. Low p16 expression was significantly related to decreased overall (P = 0.036) but not disease-free survival (P = 0.103). In multivariate analysis, deep stromal invasion but none of the cdk inhibitors was independently related to survival.

CONCLUSION

The cdk inhibitors p27, p21, and p16 are not independently associated with prognosis in stage IB SCC.

Elevated COX-2 expression in cervical carcinoma: reduced cause-specific survival and pelvic control

The purpose of this study was to correlate the level of cyclooxygenase-2 (COX-2) expression in carcinoma of the cervix with the clinical endpoints: local control, cause-specific survival, and patterns of failure in patients treated with radiotherapy. Formalin-fixed, paraffin-embedded tumor biopsies were stained for COX-2. Clinical factors such as stage, grade, tumor size, pre- and posttreatment hemoglobin level, and radiotherapy dose were also evaluated. Actuarial local control rates and cause-specific survival were determined according to the Kaplan-Meier method. COX-2 distribution staining was the only prognostic factor that was associated with local control and cause-specific survival. High COX-2 distribution staining was associated with decreased local control and decreased cause-specific survival by log rank comparison of Kaplan-Meier survival curves. The 5-year cause-specific survival rates for tumors with low versus high COX-2 distribution values were 90% and 22%, respectively (p = 0.0003). Actuarial pelvic control at 5 years was superior in patients with low COX-2 distribution staining (92%) compared with high staining (42%, p = 0.005). COX-2 staining intensity was found to correlate positively with tumor size (p = 0.02). These findings indicate that increased expression of COX-2 yields reduced pelvic control and cause-specific survival in patients with invasive carcinoma of the cervix treated with radiotherapy. Previously, inhibition of COX-2 has been demonstrated to sensitize tumors to radiation without effect on normal tissue. Taken together, these data may support a novel therapeutic application of COX-2 inhibitors in the treatment of carcinoma of the cervix.

Elevated cyclooxygenase-2 expression correlates with diminished survival in carcinoma of the cervix treated with radiotherapy

PURPOSE

The purpose of this study was to examine the relationship between overall survival and prognostic factors in carcinoma of the cervix treated with radiation therapy. A clinicopathologic study was performed on 24 patients.

METHODS AND MATERIALS

Formalin-fixed, paraffin-embedded tumor biopsies were stained for Cyclooxygenase-2 (COX-2), Topoisomerase I, Topoisomerase II, and p53. Clinical factors such as stage, grade, tumor size, pre- and post-treatment hemoglobin level, and radiotherapy dose were also evaluated.

RESULTS

Median follow-up was 75 months for living patients. The only immunohistochemical or clinical factor that was associated with improved survival was decreased COX-2 distribution staining. High COX-2 distribution staining was associated with decreased overall survival (p = 0.021) and decreased disease-free survival (p = 0.015) by log-rank comparison of Kaplan-Meier survival curves. The 5-year overall survival rates for tumors with low vs. high COX-2 distribution values were 75% and 35%, respectively. COX-2 staining intensity was found to correlate positively with tumor size (p = 0.022).

CONCLUSION

These findings indicate that increased expression of COX-2 portends a diminished survival in patients with invasive carcinoma of the cervix treated with radiotherapy. Because COX-2 is an early-response gene involved in angiogenesis and inducible by different stimuli, these data may indicate opportunity to intervene with specific inhibitors of COX-2 in carcinoma of the cervix.

p27(Kip1): regulation and function of a haploinsufficient tumor suppressor and its misregulation in cancer

A major function of p27, also known as Kip1, is to bind and inhibit cyclin/cyclin-dependent kinase complexes, thereby blocking cell cycle progression. As p27 operates at the heart of the cell cycle, it is perhaps not surprising that it is emerging as a key player in multiple cell fate decisions including proliferation, differentiation, and cell death. The central role of p27 makes it important in a variety of disease processes that involve aberrations in cellular proliferation and other cell fates. Most notable among these processes is neoplasia. A large number of studies have reported that p27 expression is frequently downregulated in human tumors. In most tumor types, reduced p27 expression correlates with poor prognosis, making p27 a novel and powerful prognostic marker. In addition to these practical implications, murine and tissue culture models have shown that p27 is a potent tumor suppressor gene for multiple epithelially derived neoplasias. Loss of p27 cooperates with mutations in several oncogenes and tumor suppressor genes to facilitate tumor growth, indicating that p27 may be a "nodal point" for tumor suppression. In contrast to most tumor suppressor genes studied to date, which are recessive at the cellular level, p27 is haploinsufficient for tumor suppression. The fact that tumor suppression by p27 is critically dependent on the absolute level of p27 expression indicates that p27 acts as a rheostat rather than as an on/off switch to control growth and neoplasia.