Distinct prognostic values of p53 mutations and loss of estrogen receptor and their cumulative effect in primary breast cancers

Genetic mutations in HER2-positive breast cancer: possible association with response to trastuzumab therapy

BACKGROUND

HER2-positive breast cancer occurs in 15-20% of breast cancer patients and is characterized by poor prognosis. Trastuzumab is considered the key drug for treatment of HER2-positive breast cancer patients. It improves patient survival; however, resistance to trastuzumab remains a challenge in HER2-positive breast cancer patients. Therefore, the prediction of response to trastuzumab is crucial to choose optimal treatment regimens. The aim of the study was to identify genetic variants that could predict response to anti-HER2-targeted therapy (trastuzumab) using next-generation sequencing.

METHOD

Genetic variants in the hotspot regions of 17 genes were studied in 24 Formalin-Fixed Paraffin-Embedded (FFPE) samples using Ion S5 next-generation sequencing system. FFPE samples were collected from HER2‑positive breast cancer patients previously treated with anti‑HER2‑targeted treatment (Trastuzumab). Patients were divided into two groups; trastuzumab-sensitive group and trastuzumab-resistant group based on their response to targeted therapy.

RESULTS

We identified 29 genetic variants in nine genes that only occurred in trastuzumab-resistant patients and could be associated with resistance to targeted therapy including TP53, ATM, RB1, MLH1, SMARCB1, SMO, GNAS, CDH1, and VHL. Four variants out of these 29 variants were repeated in more than one patient; two variants in TP53, one variant in ATM gene, and the last variant in RB1 gene. In addition, three genes were found to be mutated only in resistant patients; MLH1, SMARCB1 and SMO genes. Moreover, one novel allele (c.407A > G, p. Gln136Arg) was detected within exon 4 of TP53 gene in one resistant patient.

CONCLUSION

NGS sequencing is a useful tool to detect genetic variants that could predict response to trastuzumab therapy.

The code structure of the p53 DNA-binding domain and the prognosis of breast cancer patients

MOTIVATION

The tumor-suppressor gene TP53 mutations are diverse in the central region encoding the DNA-binding domain. It has not been clear whether the prognostic significance for survival in breast cancer patients is the same for all types of mutations. Are there specific types of mutations carrying a worse prognosis? To understand the correlation between the mutations in the gene encoding the DNA-binding domain and the prognosis of breast cancer, we studied the code structure of the DNA-binding domain of breast cancer patients by using various artificial codes in information transmission.

RESULTS

We indicated that the prognostic significance of all types of mutations in the DNA-binding domain is not the same, and that the DNA-binding domain having a certain code structure is important for estimating the prognosis of breast cancer patients.

CONTACT

keiko@is.noda.tus.ac.jp or hara@is.noda.tus.ac.jp.

Prognostic interaction between expression of p53 and estrogen receptor in patients with node-negative breast cancer: results from IBCSG Trials VIII and IX

INTRODUCTION

The prognostic significance of p53 protein expression in early breast cancer remains uncertain, with some but not all studies finding an association with poorer outcomes. Estrogen receptor (ER) expression is both a positive prognostic marker and predictive of response to endocrine therapies. The relationship between these biomarkers is unknown.

METHODS

We constructed tissue microarrays (TMAs) from available pathological material from 1113 patients participating in two randomized clinical trials comparing endocrine therapy alone versus chemo-endocrine therapy in node-negative breast cancer. Expression of p53 defined as >10% positive nuclei was analyzed together with prior immunohistochemical assays of ER performed at central pathological review of whole tumor sections.

RESULTS

ER was present (i.e. >1% positive tumor cell nuclei) in 80.1% (880/1092). p53 expression was significantly more frequent when ER was absent, 125/212 (59%) than when ER was present, 171/880 (19%), p <0.0001. A significant qualitative interaction was observed such that p53 expression was associated with better disease-free survival (DFS) and overall survival (OS) among patients whose tumors did not express ER, but worse DFS and OS among patients whose tumors expressed ER. The interaction remained significant after allowance for pathologic variables, and treatment. Similar effects were seen when luminal and non-luminal intrinsic subtypes were compared.

CONCLUSIONS

Interpretation of the prognostic significance of p53 expression requires knowledge of concurrent expression of ER. The reason for the interaction between p53 and ER is unknown but may reflect qualitatively different p53 mutations underlying the p53 expression in tumors with or without ER expression.

TRIAL REGISTRATION

Current Controlled Trials ACTRN12607000037404 (Trial VIII) and ACTRN12607000029493 (Trial IX).

p53 dominant-negative mutant R273H promotes invasion and migration of human endometrial cancer HHUA cells

Dominant negative (DN) mutations of tumor suppressor p53 (TP53) are clinically associated with cancer progression and metastasis of endometrial malignancy. To investigate the DN effect on tumor migration and invasion, we generated cells that stably co-expressed wild-type (wt) and R273H DN mutant TP53 (273H cells), and wt and R213Q recessive mutant TP53 (213Q cells), by transfection in endometrial cancer cells HHUA that expressed wt p53. R273H, but not R213Q, repressed wt p53-stimulated transcription of p21, Bax, and MDM2. 273H cells also showed markedly increased in vitro invasion and migration potentials, and displayed reduced Maspin, PAI-1, and KAI1 mRNA expressions as compared with 213Q and wt cells. The induction of wt p53 function by use of Adriamycin resulted in the inhibition of the invasion/migration capacity in association with the up-regulation of p53 target genes to a far greater degree in 213Q and wt cells than in 273H cells. R273H expression in p53-null cancer cell SK-OV-3 and Saos-2 did not significantly affect cell invasion and migration activities. Taken together, these results suggest that transdominance of R273H mutant over wt p53 rather than a gain-of-function promotes tumor metastasis by increasing invasion and migration in HHUA cells.

Functional analysis of p53 gene and the prognostic impact of dominant-negative p53 mutation in endometrial cancer

In addition to the loss of function, mutant p53 can possess a dominant-negative effect on wild-type p53 and may also exert gain-of-function activity. It is not clear whether the functional status of p53 mutation contributes to differences in outcome in endometrial cancer. We collected a total of 92 RNA samples of high quality from endometrial cancer tissues, and the samples were subjected to yeast functional assay and sequencing for p53 mutations. The detected mutant p53 genes were further investigated for their dominant-negative activity using a yeast-based transdominance assay. p53 mutation was found in 24 out of 92 (26.1%) tumors, of which 10 exhibited no dominant-negative activity (recessive mutation) and 14 showed dominant-negative activity. Dominant-negative p53 mutation was related to advanced stages (p = 0.01), nonendometrioid type tumors (p = 0.01) and grade 3 tumors (p = 0.04). The patients with dominant-negative mutation had significantly shorter survival than patients with no mutation (p < 0.0001) and those with a recessive mutation (p = 0.01) in the p53 gene. No difference in survival was found between the patients with tumors harboring a recessive p53 mutation and those with tumors harboring a wild-type p53. Multivariate analysis revealed that dominant-negative p53 mutation (p = 0.019), FIGO stage (p = 0.0037) and histologic subtype (p = 0.014) were independently related to patient survival. Dominant-negative p53 mutation was the most important prognostic factor for stage III/IV endometrial cancer (p = 0.0023). In conclusion, dominant-negative p53 mutation is often found in advanced stages and aggressive histologic subtypes of endometrial cancer and it is a strong predictor of survival of patients with advanced endometrial cancer. To elucidate further the role of p53 mutation in endometrial cancer, it is necessary to investigate gain-of-function activity involving dominant-negative p53 mutant proteins.

Prognostic significance of co-expression of RON and MET receptors in node-negative breast cancer patients

PURPOSE

RON and MET belong to a subfamily of tyrosine kinase receptors. They both can induce invasive growth, including migration, cell dissociation, and matrix invasion. Cross-linking experiments show that RON and MET form a noncovalent complex on the cell surface and cooperate in intracellular signaling. We wanted to examine the clinical significance of RON and MET expression patterns in node-negative breast cancer.

EXPERIMENTAL DESIGN

We studied the protein expressions of RON and MET in five breast cancer cell lines and a homogeneous cohort of 103 T(1-2)N(0)M(0) breast carcinoma patients, including 52 patients with distant metastases and 51 patients with no evidence of disease after at least a 10-year follow-up.

RESULTS

Both HCC1937 and MDA-MB-231 cancer cell lines co-overexpressed RON and MET. The MCF-7 cell line did not express RON or MET. In multiple logistic regression analysis, RON expression (odds ratio, 2.6; P = 0.05) and MET expression (odds ratio, 4.7; P = 0.009) were independent predictors of distant relapse. RON+/MET+ and RON-/MET+ tumors resulted in a large risk increase for 10-year disease-free survival after adjusting for tumor size, histologic grade, estrogen receptor, bcl-2, HER-2/neu, and p53 status by multivariate Cox analysis (risk ratio, 5.3; P = 0.001 and risk ratio, 3.76; P = 0.005). The 10-year disease-free survival was 79.3% in patients with RON-/MET- tumors, was only 11.8% in patients with RON+/MET+ tumors, and was 43.9% and 55.6% in patients with RON-/MET+ and RON+/MET- tumors.

CONCLUSIONS

Co-expression of RON and MET seems to signify an aggressive phenotype in node-negative breast cancer patients.

p53-defective tumors with a functional apoptosome-mediated pathway: a new therapeutic target

BACKGROUND

Although cancer cells appear to maintain the machinery for intrinsic apoptosis, defects in the pathway develop during malignant transformation, preventing apoptosis from occurring. How to specifically induce apoptosis in cancer cells remains unclear.

METHODS

We determined the apoptosome activity and p53 status of normal human cells and of lung, colon, stomach, brain, and breast cancer cells by measuring cytochrome c-dependent caspase activation and by DNA sequencing, respectively, and we used COMPARE analysis to identify apoptosome-specific agonists. We compared cell death, cytochrome c release, and caspase activation in NCI-H23 (lung cancer), HCT-15 (colon cancer), and SF268 (brain cancer) cells treated with Triacsin c, an inhibitor of acyl-CoA synthetase (ACS), or with vehicle. The cells were mock, transiently, or stably transfected with genes for Triacsin c-resistant ACSL5, dominant negative caspase-9, or apoptotic protease activating factor-1 knockdown. We measured ACS activity and levels of cardiolipin, a mitochondrial phospholipid, in mock and ACSL5-transduced SF268 cells. Nude mice carrying NCI-H23 xenograft tumors (n = 10) were treated with Triacsin c or vehicle, and xenograft tumor growth was assessed. Groups were compared using two-sided Student t tests.

RESULTS

Of 21 p53-defective tumor cell lines analyzed, 17 had higher apoptosome activity than did normal cells. Triacsin c selectively induced apoptosome-mediated death in tumor cells (caspase activity of Triacsin c-treated versus untreated SF268 cells; means = 1020% and 100%, respectively; difference = 920%, 95% CI = 900% to 940%; P<.001). Expression of ACSL5 suppressed Triacsin c-induced cytochrome c release and subsequent cell death (cell survival of Triacsin c-treated mock- versus ACSL5-transduced SF268 cells; means = 40% and 83%, respectively; difference = 43%, 95% CI = 39% to 47%; P<.001). ACS was also essential to the maintenance of cardiolipin levels. Finally, Triacsin c suppressed growth of xenograft tumors (relative tumor volume on day 21 of Triacsin c-treated versus untreated mice; means = 4.6 and 9.6, respectively; difference = 5.0, 95% CI = 2.1 to 7.9; P = .006).

CONCLUSIONS

Many p53-defective tumors retain activity of the apoptosome, which is therefore a potential target for cancer chemotherapy. Inhibition of ACS may be a novel strategy to induce the death of p53-defective tumor cells.

Mutational spectrum of p53 mutations in primary breast and ovarian tumors

Breast and ovarian cancers, like other cancers, occur due to genetic damage. Research aimed to determine the specific genes involved in the development of breast and ovarian cancers will help to understand how normal breast and ovarian epithelial cells escape regulation of proliferation, apoptosis and senescence. It was determined that approximately 10% of ovarian cancers and 20-30% of breast cancers arise in women who have inherited mutations in cancer susceptibility genes such as BRCA1, BRCA2 and other DNA repair genes. The ability to perform genetic testing permits the identification of women at increased risk who can then be offered preventive strategies. The vast majority of ovarian and breast cancers are sporadic, presumably resulting from the accumulation of genetic damage over lifetime. Several genes involved in breast and ovarian carcinogenesis have been identified, most notably the p53 tumor suppressor. The recent availability of expression microarrays has facilitated the simultaneous screening of thousands of genes and this will extend further the understanding of molecular events involved in the dynamic development of ovarian and breast cancers. Then, all this knowledge could be translated into effective screening, surveillance, prevention, and treatment strategies in the future.

Recent progress in predictive biomarkers for metastatic recurrence of human hepatocellular carcinoma: a review of the literature

Molecular markers (biomarkers) for hepatocellular carcinoma (HCC) metastasis and recurrence could provide additional information to that gained from traditional histopathological features. A large number of biomarkers have been shown to have potential predictive significance. One important aspect of this is to detect the transcripts of tumor-associated antigens (such as AFP, MAGEs, and CK19), which are proposed as predictive markers of HCC cells disseminated into the circulation and for metastatic recurrence. Another important aspect is to analyze the molecular markers for cellular malignancy phenotype, including DNA ploidy, cellular proliferation index, cell cycle regulators, oncogenes, and tumor suppressors (especially p53 gene), as well as telomerase activity. Molecular factors involved in the process of HCC invasion and metastasis, including adhesion molecules (E-cadherin, catenins, ICAM-1, laminin-5, CD44 variants, osteopontin), proteinases responsible for the degradation of extracellular matrix (MMPs, uPA system), as well as angiogenesis regulators (such as VEGF, intratumor MVD), have also been shown to be potential predictors for HCC metastatic recurrence and clinical outcomes. One important new trend is to widely delineate biomarkers with genomic and proteomic expression with reference to predicting metastatic recurrence, molecular diagnosis, and classification, which has been drawing more attention recently. Body fluid (particularly blood and urine) testing for biomarkers is easily accessible and more useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum and its genetic alterations is another important direction. More attention should be paid to these areas in the future. As understanding of tumor biology deepens, more and more new biomarkers with high sensitivity and specificity for HCC metastatic recurrence could be found and routinely used in clinical assays. However, the combination of the pathological features and some of the biomarkers mentioned above seems to be more practical up to now.

Chromosomal comparative genomic hybridization abnormalities in early- and late-onset human breast cancers: correlation with disease progression and TP53 mutations

Nearly 30% of the breast cancer patients in the Taiwanese community have their diseases diagnosed before the age of 40. Their 5-year survival rate is poorer than that of their late-onset breast cancer counterparts. Genomic abnormalities between these two breast cancer age groups were compared using comparative genomic hybridization (CGH) analyses. The sample set was made up of 44 early-onset (<35 years old) and 54 late-onset cases (>63 years old). Frequent CGH changes were noted, such as gains on 8q, 1q, and 17q and losses on 16q, 17p, and 8p. These were very similar for the two age groups, as well as for Taiwanese women and other ethnic populations. In contrast, several less common lesions, such as gains on 16p and 8p and losses on 11q and 9p, were significantly different between the early- and late-onset breast tumors. In addition, more profound chromosomal changes were consistently associated with the more advanced-stage tumors, and less expression of the estrogen and the progesterone receptors, and of HER-2/neu. About 19% of the breast cancers examined carried a TP53 mutation in exons 4-9. Of these, 88% (15/17) were missense point mutations and these were distributed randomly along the tested gene fragments without apparent clustering, as has been shown in certain other ethnic or regional studies. On average, patients carrying these TP53 mutations had 9.5 CGH lesions per case, compared to only 2.8 changes in samples that had no TP53 mutation. Our results indicate that certain genomic lesions, especially 11q loss, may play a role in early-onset breast tumor formation, and that combined use of genomic patterns and molecular targets may provide a useful tool for diagnostic, therapeutic, and prognostic purposes.

Loss of p53 transcriptional activity in hepatocellular carcinoma evaluated by yeast-based functional assay: comparison with p53 immunohistochemistry

We studied the transcriptional activity of p53 protein in 50 tissues of hepatocellular carcinoma (HCC) using a yeast functional assay. In this assay, red yeast colonies indicate that p53 protein cannot bind to its specific domain and has lost its transcriptional activity. We also clarified whether mutant p53 protein could inactivate wild-type p53 protein in a transdominant manner using a modified yeast assay. In addition, we examined whether immunohistochemically detectable p53 protein was functionally inactive. The incidence of p53 inactivation was significantly higher in tumors with capsular invasion. Out of 21 tumors diagnosed with p53 mutations, 11 exhibited >75% red colonies, and all contained missense mutations. In these tumors, p53 function was lost because there was supposedly no intact p53 gene on either allele. One missense mutant produced <60% red colonies, but it was also considered inactive as a p53 protein heterotetramer because of its transdominant activity. In 7 of the remaining 9 tumors, p53 was considered to be mutated on one allele and intact on the other. All of these 7 tumors contained nonsense or frameshift mutations and had no transdominant activity, which suggested that p53 function remained intact. Alternately, immunohistochemical analysis demonstrated that all of the tumors with missense mutations were positively immunostained, whereas those that contained nonsense or frameshift mutations were negatively stained. Consequently, positively immunostaining tumors mostly coincided with p53-inactive tumors. These yeast-based assays suggested that p53 function was retained in some mutant cases. Immunohistochemistry was helpful in screening functionally inactive p53 protein in HCCs.

High syndecan-1 expression in breast carcinoma is related to an aggressive phenotype and to poorer prognosis

BACKGROUND

Syndecan-1 is a transmembrane heparan sulphate proteoglycan that is involved in cell-cell adhesion, organization of cell-matrix adhesion, and regulation of growth factor signaling.

METHODS

Specimens from 254 consecutive breast carcinoma (BC) cases (110 N0, 144 N1/2) with long-term follow-up (median, 95 months) were immunostained for syndecan-1, estrogen receptor (ER), progesterone receptor (PgR), and p53; in 154 cases, c-erbB-2 status was known. Syndecan-1 mRNA and protein expression also were evaluated in 20 breast tissue samples (10 normal and tumor pairs).

RESULTS

Syndecan-1 was expressed at high levels in 106 (42%) BCs; syndecan-1 up-regulation was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) studies. High syndecan-1 expression was associated with high histologic grade, large tumor size, high mitotic count, c-erbB-2 overexpression, and ER and PgR negative status. At univariate survival analysis syndecan overexpression was related to poor prognosis (P < 0.01 for both overall survival (OS) and disease-free survival). Bivariate survival analysis showed an additive adverse effect for syndecan-1 and c-erbB-2 overexpression. At multivariate analysis, syndecan-1 overexpression was independently associated with poor OS (hazard ratio [HR], 1.71; 95% confidence interval [CI], 1.08-2.69). High syndecan-1 expression also was of independent prognostic value for OS in the group of 102 ER-negative patients (HR, 2.42; 95% CI, 1.21-4.82). Stratifying patients on the basis of the type of adjuvant therapy given, high syndecan-1 expression was associated with a higher risk of death only in patients treated with the cyclophosphamide-methotrexate-fluorouracil regimen (HR, 1.9; P = 0.09); at multivariate analysis for OS, this association proved to be of independent statistical significance (P = 0.03; HR, 2.15).

CONCLUSIONS

Syndecan-1 is expressed at high levels in a significant percentage of breast carcinomas and is related to an aggressive phenotype and poor clinical behavior.

Correlations of Breast Carcinoma Biomarkers and p53 Tested by FASAY and Immunohistochemistry

p53 status is an important predictive factor in breast cancer, but the results of many studies are ambiguous. We tested p53 by functional analysis of separated alleles in yeast (FASAY) as well as by immunohistochemistry (IHC) and evaluated correlations with main prognostic factors, proliferation, and Bcl-2. Thirty-two tumors were tested with antibodies BP53-12, DO1, DO11, DO12, and by FASAY. Spearman rank correlations were tested separately with age, tumor type, pT, grade, pN, NPI, Ki-67, S-phase, proliferation index, Bcl-2, and steroid receptor status determined by ER, PR, and pS2. FASAY showed significant correlations with ductal type, grade and proliferation, and an inverse correlation with functional estrogen receptor and Bcl-2. FASAY provided better correlations compared to p53 IHC. We conclude that FASAY shows significant correlations with main prognostic/predictive factors and provides more reliable biological information compared to p53 IHC. Apoptosis is positively linked to proliferation and is not under the control of p53, which is frequently mutated in highly proliferating carcinomas. FASAY seems to be very important in assessing the predictive significance of p53 for a specific therapy of breast cancer.

p53 expression in biopsies from children with Langerhans cell histiocytosis

PURPOSE

Langerhans cell histiocytosis (LCH) is a rare pediatric and adult disease causing skin rashes, osteolytic bone lesions, tumorous growth in various organs, and in some patients, organ dysfunction. The cause of the disease is obscure, and it is not yet understood why some patients develop single-system lesions only without relapse, whereas others develop fatal multiorgan disease. The expression of p53 tumor suppressor gene product detected immunohistochemically can be used as a guideline to alterations in DNA repair control and apoptosis. The authors have chosen to analyze p53 expression in biopsies from children with LCH and correlate it with clinical manifestation and outcome in a broad range of organs.

PATIENTS AND METHODS

The study was performed on 50 specimens from 32 children (19 boys and 13 girls), median age 3 1/4 years, range 5 months to 12 1/3 years with a definite diagnosis of LCH based on CD1a positivity. The slides were stained with p53 antibody and semiquantitatively evaluated using a grading system from 1 to 5 as an estimate for 0% to 20%, 20% to 40%, 40% to 60%, 60% to 80%, and 80% to 100% p53-positive for pathologic Langerhans cells (pLC), respectively.

RESULTS

The p53 protein was expressed in various degrees in pLC in all lesions. The degree of p53 expression could not be correlated to either clinical manifestation or outcome.

CONCLUSIONS

An increased expression of p53 in pLC indicates an altered DNA repair control with or without abnormal control of apoptosis.

Bax, Bcl-2, and p53 expression in endometrial cancer

BACKGROUND

It has not been fully clarified whether alteration of Bax and other apoptosis-relating proteins of Bcl-2 and p53 is involved in endometrial carcinogenesis.

METHODS

A total of 56 frozen tissues, which included 14 normal endometria, 13 endometrial hyperplasias (10 without atypia and 3 with atypia), and 29 endometrial carcinomas, were examined for the expression of Bax, Bcl-2, and p53 using immunohistochemistry. For Bax-negative cases, PCR-direct sequencing was performed for the bax gene. For cases with p53 overexpression, mutational analysis was performed for the p53 gene using a yeast functional assay and sequencing.

RESULTS

Both Bax and Bcl-2 were distinctly expressed in the normal proliferative phase endometrium. A decreased Bcl-2/Bax ratio in the secretory phase endometrial gland cells due to suppressed Bcl-2 expression was observed. Bax expression was positive in all 13 endometrial hyperplasias, while it was absent in 6 of 29 endometrial carcinomas (20.7%). Negative Bax expression in endometrial carcinoma was not related to tumor stage, histologic subtype, or other histopathologic prognostic factors. Bax expression showed no relationship to either p53 overexpression or Bcl-2 expression. In the DNA of 6 Bax-negative cases, we found a frameshift insertion mutation at codon 58 (AAG to CAAG) in the BH3 domain despite the absence of mutation in the (G)8 tract, suggesting that this codon may be another preferred target for bax mutation other than the (G)8 tract. Mutational analysis was available for 7 of 10 cases with p53 overexpression, in which 5 cases were found to have a missense mutation and 2 cases had no mutation of the p53 gene. At least 10 of 29 (34.5%) cases of endometrial carcinoma were associated with sequence-verified mutation in the bax gene and/or p53 gene.

CONCLUSIONS

The bax gene frameshift mutation appears to cause a loss of Bax expression in endometrial carcinoma. Codon 58 may be a preferred target of bax gene mutation in endometrial carcinomas. The bax gene mutation seems to occur in the early stage of the genesis of a subset of endometrial carcinomas.

Prognostic significance of Bcl-2, p53 overexpression, and lymph node metastasis in surgically staged endometrial carcinoma

OBJECTIVE

The purpose of this study was to clarify whether Bcl-2 and p53 have prognostic significance that is independent of lymph node metastasis and other conventional histopathologic factors in endometrial carcinoma.

STUDY DESIGN

Immunohistochemistry for Bcl-2 and p53 expression was performed on the frozen sections of 102 cases that were treated with surgery, including pelvic and para-aortic lymphadenectomy. Cox regression analysis was used to determine the prognostic significance.

RESULTS

By univariate analysis, both loss of Bcl-2 expression and p53 overexpression were related to patient survival. Lymph node metastasis, p53 overexpression, and nuclear grade were found to be independent prognostic factors (determined by multivariate analysis). The estimated 5-year survival rate of patients with stage III/IV disease without p53 overexpression was 75.7%; the estimated 5-year survival rate for patients with p53 overexpression was only 40.4%. The difference was highly significant (P =.0053).

CONCLUSION

Lymph node metastasis, p53 overexpression, and nuclear grade are independent prognostic factors for endometrial carcinoma. Bcl-2 may have little importance in the progression of endometrial carcinoma and is a less potent prognostic factor than is p53. A new treatment strategy is necessary for advanced stage endometrial carcinoma with p53 overexpression.

p53 immunohistochemical scoring: an independent prognostic marker for patients after hepatocellular carcinoma resection

AIM: To confirm if p53 mutation could be a routine predictive marker for the prognosis of hepatocellular carcinoma (HCC) patients.

METHODS: Two hundreds and forty-four formalin-fixed paraffin-embedded tumor samples of the patients with HCC receiving liver resection were detected for nuclear accumulation of p53. The percent of p53 immunoreactive tumor cells was scored as 0 to 3 + in p53 positive region (< 10% -, 10%-30% +, 31%-50% ++, > 50% +++). Proliferating cell nuclear antigen (PCNA) and some clinicopathological characteristics, including patients’ sex, preoperative serum AFP level, tumor size, capsule, vascular invasion (both visual and microscopic), and Edmondson grade were also evaluated.

RESULTS: In univariate COX harzard regression model analysis, tumor size, capsule status, vascular invasion, and p53 expression were independent factors that were closely related to the overall survival (OS) rates of HCC patients. The survival rates of patients with 3+ for p53 expression were much lower than those with 2+ or + for p53 expression. Only vascular invasion (P < 0.05) and capsule (P < 0.01) were closely related to the disease-free survival (DFS) of HCC patients. In multivariate analysis, p53 overexpression (RI 0.5456, P < 0.01) was the most significant factor associated with the OS rates of patients after HCC resection, while tumor size (RI 0.5209, P < 0.01), vascular invasion (RI 0.5271, P < 0.01) and capsule (RI 0.8691, P < 0.01) were also related to the OS. However, only tumor capsular status was an independent predictive factor (P < 0.05) for the DFS. No significant prognostic value was found in PCNA-LI, Edmondson’s grade, patients’ sex and preoperative serum AFP level.

CONCLUSION: Accumulation of p53 expression, as well as tumor size, capsule and vascular invasion, could be valuable markers for predicting the prognosis of HCC patients after resection. The quantitative immunohistochemical scoring for p53 nuclear accumulation might be more valuable for predicting prognosis of patients after HCC resection than the common qualitative analysis.

The prognostic molecular markers in hepatocellular carcinoma

The prognosis of hepatocellular carcinoma (HCC) still remains dismal, although many advances in its clinical study have been made. It is important for tumor control to identify the factors that predispose patients to death. With new discoveries in cancer biology, the pathological and biological prognostic factors of HCC have been studied quite extensively. Analyzing molecular markers (biomarkers) with prognostic significance is a complementary method. A large number of molecular factors have been shown to associate with the invasiveness of HCC, and have potential prognostic significance. One important aspect is the analysis of molecular markers for the cellular malignancy phenotype. These include alterations in DNA ploidy, cellular proliferation markers (PCNA, Ki-67, Mcm2, MIB1, MIA, and CSE1L/CAS protein), nuclear morphology, the p53 gene and its related molecule MD M2, other cell cycle regulators (cyclin A, cyclin D, cyclin E, cdc2, p27, p73), oncogenes and their receptors (such as ras, c-myc, c-fms, HGF, c-met, and erb-B receptor family members), apoptosis related factors (Fas and FasL), as well as telomerase activity. Another important aspect is the analysis of molecular markers involved in the process of cancer invasion and metastasis. Adhesion molecules (E-cadherin, catenins, serum intercellular adhesion molecule-1, CD44 variants), proteinases involved in the degradation of extracellular matrix (MMP-2, MMP-9, uPA, uPAR, PAI), as well as other molecules have been regarded as biomarkers for the malignant phenotype of HCC, and are related to prognosis and therapeutic outcomes. Tumor angiogenesis is critical to both the growth and metastasis of cancers including HCC, and has drawn much attention in recent years. Many angiogenesis-related markers, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived endothelial cell growth factor (PD-ECGF), thrombospondin (TSP), angiogenin, pleiotrophin, and endostatin (ES) levels, as well as intratumor microvessel density (MVD) have been evaluated and found to be of prognostic significance. Body fluid (particularly blood and urinary) testing for biomarkers is easily accessible and useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum, and its genetic alterations in HCC are other important trends. More attention should be paid to these two areas in future. As the progress of the human genome project advances, so does a clearer understanding of tumor biology, and more and more new prognostic markers with high sensitivity and specificity will be found and used in clinical assays. However, the combination of some items, i.e., the pathological features and some biomarkers mentioned above, seems to be more practical for now.

Assessing TP53 status in human tumours to evaluate clinical outcome

TP53 is probably the most extensively studied tumour-suppressor gene, and patients with TP53 mutations are known to have a poor outcome. However, inconsistencies in the analysis of TP53 status, and failure to realize that different mutations behave in different ways, prevent us from effectively applying our vast knowledge of this protein in clinical practice. What simple steps can be taken to ensure that patients benefit from our understanding of TP53?

Dominant-negative mutation of p53 tumor suppressor gene in endometrial carcinoma

BACKGROUND

It has been suggested that mutation of the TP53 tumor suppressor gene is involved in endometrial carcinogenesis. However, the status of p53 function in endometrial cancers has not yet been investigated in detail.

METHODS

We surveyed inactivating p53 mutations in endometrial carcinomas using the yeast p53 functional assay, which can evaluate the transcriptional activity of p53 in vivo in yeast. To the detected p53 mutants, we also applied a transdominance assay, which assesses the dominant-negative property of mutants.

RESULTS

Of 23 endometrial carcinomas, 9 tumors (39.1%) were found to harbor p53 mutations. Only 1 of the 6 mutants in 18 endometrioid-type tumors showed dominant-negative capacity. In contrast to the endometrioid-type tumor, all 3 mutations in 5 serous-type tumors (R273H, 9-bp deletion in codons 240-243, and R248W) showed dominant-negative capacity and presented in a homozygous state in the tumors, indicating a complete functional inactivation.

CONCLUSIONS

Although this study included a relatively small number of cases and therefore is a preliminary study, these results suggest that the dominant-negative mutation of the TP53 gene is related to serous adenocarcinoma. The role of the dominant-negative status of p53 mutants in endometrial carcinogenesis and progression of this disease should be further investigated.

Induction of apoptosis in melanoma cell lines by p53 and its related proteins

Melanoma cells rarely contain mutant p53 and hardly undergo apoptosis by wild-type p53. By using recombinant adenoviruses that express p53 or p53-related p51A or p73beta, we tested their apoptotic activities in melanoma cells. Yeast functional assay revealed a mutation of p53 at the 258th codon (AAA [K] instead of GAA [E]) in one cell line, 70W, out of six human melanoma cell lines analyzed (SK-mel-23, SK-mel-24, SK-mel-118, TXM18, 70W, and G361). Adenovirus-mediated transfer of p53, p51A, and/or p73beta suppressed growth and induced apoptotic DNA fragmentation of SK-mel-23, SK-mel-118, and 70W cells. Interestingly, p51A induced DNA fragmentation in them more significantly than p53 and p73beta. By Western blotting we analyzed levels of apoptosis-related proteins in cells expressing p53 family members. Apoptotic Bax and antiapoptotic Bcl-2 were not significantly upregulated or downregulated by expression of p53, p51A, or p73beta, except for p53-expressing 70W cells, which contained a larger amount of Bax protein than LacZ-expressing cells. Activation of caspase-3 was demonstrated only in p51A-expressing SK-mel-118 cells. We show here that p51A can mediate apoptosis in both wild-type and mutant p53-expressing melanoma cells more significantly than p53 and p73beta. It is also suggested that in melanoma cells (i) cellular target protein(s) other than Bcl-2 and Bax might be responsible for induction of p51A-mediated apoptosis and (ii) caspase-3 is not always involved in the apoptosis by p53 family members.