P53 Gene Alterations Research Articles

PD.223 Correlation between human papillomavirusand p53 gene alterations in oral squamous cell carcinoma and their relations to age, gender, alcohol and tobacco consumption

PD.223 Correlation between human papillomavirusand p53 gene alterations in oral squamous cell carcinoma and their relations to age, gender, alcohol and tobacco consumption

Assessment of K-ras, Smad4 and p53 gene alterations in colorectal metastases and their role in the metastatic process

To date there is no genetic marker that gives accurate information on the prognostic impact for patients with colorectal cancer. A particular clone, not detected in the tumor, could be responsible for the metastatic process. To overcome this problem, genetic alterations were analyzed in metastatic tissues from 58 patients who developed metastases after curative surgery for colorectal cancer. K-ras, p53 and Smad4 alterations were observed in respectively 38, 60 and 27% of the metastases. These frequencies are similar to the ones reported in primary colorectal tumors. Thus, these genetic alterations cannot be used as prognostic biomarkers in patients with colorectal cancer. The metastases were stratified into 3 groups, according to the metastatic localization. K-ras mutations were detected in respectively 75, 26 and 11% of the distant, peritoneal and liver metastases. Loss of Smad4 expression was observed more frequently in the liver (62%) than in other metastases (13%). These results suggest that the genetic changes of the tumor cells indicate the location of the metastases and thus, the route of metastatic spread.

Serum p53 and bladder cancer: can serum p53 be used as a tumor marker?

The aim of this study was to find the correlation between serum p53 and carcinoma of the bladder and to investigate whether serum p53 protein can be used as a tumor marker for p53 gene alteration. The study included patients with carcinoma of the bladder and controls. Serum p53 protein estimation was done with an ELISA kit. There were 23 patients with superficial and 17 with invasive carcinoma. The median serum p53 was 31.5 U/ml in superficial and 41 U/ml in invasive cancer. This was significantly higher than the mean value (16.4 U/ml) of controls. Serum p53 rises in patients with carcinoma of the bladder and correlates with the grade of the disease . It can therefore be used as a tumor marker for bladder cancer.

Clinicopathologic significance and prognostic value of chromosomal imbalances in diffuse large B-cell lymphomas.

To determine the clinicopathologic significance and prognostic value of chromosomal imbalances in diffuse large B-cell lymphomas (DLBCL). We have examined 64 tumors at diagnosis using comparative genomic hybridization and real-time quantitative polymerase chain reaction (PCR), single-stranded conformational polymorphism, and DNA sequencing for the analysis of several potential target genes. The most recurrent alterations were gains of 18q (20%), Xq (15%), 2p, 7q, and 12p (14%), and losses of 6q and 17p (14%). Frequent high-level DNA amplifications were detected at 2p13-p16 and 18q21 loci. Real-time quantitative PCR detected REL and BCL11A gene amplifications in the nine patients with gains at 2p13-p16 and only in one additional patient with normal chromosome 2. Similarly, the BCL-2 gene was amplified in the 12 tumors with gains of 18q21 but in none of 39 patients with normal 18q profile. p53 gene inactivation was detected in nine of 58 (16%) tumors and was commonly associated with 17p losses. Tumors with 18q gains were significantly associated with a high number of chromosomal imbalances, primary nodal presentation, high serum lactate dehydrogenase levels, high International Prognostic Index, shorter cause-specific survival, and a high risk of relapse. Losses of 17p and p53 gene alterations were associated with an absence of complete response achievement. These results suggest that DLBCLs have a characteristic pattern of genomic alterations; 18q gains or amplifications and 17p losses are associated with particular clinicopathological features and aggressive clinical behavior. Additional studies are needed to confirm these observations in larger series of patients.

Molecular analysis of p53, MDM2 and H-ras genes in low-grade central osteosarcoma

Low-grade central osteosarcoma is an uncommon form that is characterized by a long premorbid history, and is compatible with prolonged survival after treatment. However, molecular abnormalities are rare in low-grade central osteosarcomas, whereas p53 mutations occur in approximately 20% of conventional high-grade osteosarcomas. In this study, 21 cases of low-grade central osteosarcoma were analyzed for mutations of the p53 gene, amplification of the MDM2 gene, and mutations of the H-ras gene using formalin-fixed, paraffin-embedded materials. We also examined the expression of p53, MDM2, and p21WAF1 protein immunohistochemically and assessed the proliferation activities using the monoclonal antibody MIB-1. One case (4.7%) showed strong p53 immunoreactivity, whereas p53 gene mutations were not detected at all. Seven cases (33.3%) showed immunoreactivity for MDM2 protein. As for gene alterations, MDM2 amplification was found in four cases (19.0%). p21WAF1 expression was detected in 12 cases (57.1%). MIB-1-LI showed very low levels in all the cases and no significant correlation with p53 or MDM2 immuno-reactivity. None of the tumors showed H-ras mutations. In conclusion, the number of p53 gene alterations in low-grade central osteosarcomas is lower than that in conventional high-grade osteosarcomas. MDM2 alterations and p21WAF1 expression might be involved in the tumorigenesis of low-grade central osteosarcomas.

Use of cytological specimens for p53 gene alteration detection in oral squamous cell carcinoma risk patients.

Recurrence and multifocal nature are two important characteristics of oral squamous cell carcinoma. Leukoplakia is the most frequent pre-cancerous oral lesion and, in most cases, it is not possible to predict malignant capacity. The objective of this study is to identify p53 alterations in cells taken from the oral cavity of at-risk patients. The following samples were collected from 34 patients with oral leukoplakia with and without previous carcinoma: oral rinse, a brush swabbed over the lesions and hair roots. Mutational analysis of the p53 gene was performed by single-strand conformation polymorphisms and confirmed by DNA sequencing. We detected 11 mutations in p53 gene in oral cytological specimens. These alterations were observed only in brush cytology samples in patients without previous carcinoma, and in both samples (rinse and brush) in patients with previous carcinoma. Three of these patients had disease recurrence. This non-invasive technique may be useful in the follow-up of at-risk patients, and introduces new possibilities to analyse molecular markers before malignant lesions are clinically apparent.

Enhanced TGFα-EGFR expression and P53 gene alterations contributes to gastric tumors aggressiveness

We determined whether alterations in the expression of p53, p16 INK4 and p21 WAF1/CIP1 influence the invasiveness of a subset of gastric adenocarcinomas co-expressing TGFα and EGFR. Immunopositivity for TGFα-EGFR (26%) was observed in both early and advanced adenocarcinomas, and 88% of these showed immunoreactivity for p53. SSCP analysis revealed that in 81% of these tumors the p53 gene was mutated in exons 5–8. The intensity of p53 immunoreactivity was significantly higher ( P<0.013) in deeply invasive tumors. p16 INK4 and p21 WAF1/CIP1 immunoreactivity was detected in 93 and 76% of the samples co-expressing TGFα-EGFR but the levels were not correlated with those of p53 and other clinico-pathological parameters. We conclude that gastric adenocarcinomas potentially dependent upon the TGFα-EGFR autocrine loop for growing exhibit increased aggressiveness in the presence of aberrant p53.

Association of p53 genetic polymorphism (Arg72Pro) with estrogen receptor positive breast cancer risk in Japanese women

Since it is well established that inactivation of p53 is involved in pathogenesis of breast cancer, it seems to be reasonable to assume that p53 genetic polymorphism at codon 72 (p53 Arg72Pro) which affects the function of p53 might have an influence on breast cancer risk. Thus, in the present study, we have studied the association of p53 Arg72Pro polymorphism with breast cancer risk. A case–control study was conducted with 191 breast cancer patients and 218 healthy female controls. p53 Arg72Pro polymorphism was examined in their association with breast cancer risk after adjustment for the epidemiological risk factors. Relationship between p53 Arg72Pro polymorphism and clinicopathological characteristics of breast cancers was also studied. In addition, frequency of somatic p53 mutation was compared according to the genotype of p53 Arg72Pro polymorphism. p53 72Pro/Pro homozygotes showed a significant increase in the risk of estrogen receptor (ER) positive breast cancer (adjusted odds ratio (OR)=2.04, P=0.04) as compared with p53 72Arg/Arg homozygotes, whereas such an association was not found between p53 72Pro/Pro homozygotes and ER negative breast cancer risk. Subset analysis according to menopausal status showed that p53 72Pro/Pro homozygotes were significantly associated with ER positive breast cancer risk in postmenopausal women (adjusted OR=3.42, P=0.01) but not in premenopausal women. Frequency of ER positive tumors was significantly ( p<0.01) higher in breast cancer patients with p53 72Pro/Pro genotype (82.8%) than those with p53 72Arg/Arg genotype (54.5%). Mutational analysis of p53 in tumors showed that p53 72Pro/Pro homozygotes had a lower frequency of p53 mutation (3.5%) than p53 72Arg/Arg homozygotes (10.5%). It is suggested that p53 Arg72Pro polymorphism is associated with ER positive breast cancer risk, especially, in postmenopausal women. The higher frequency of p53 somatic mutation in p53 72Arg/Arg homozygotes than p53 72Pro/Pro homozygotes is consistent with the thesis that the function of p53 72Pro/Pro is impaired so that a further alteration of p53 gene is less required in p53 72Pro/Pro homozygotes than p53 72Arg/Arg homozygotes.

Enhanced TGF$alpha;-EGFR expression and P53 gene alterations contributes to gastric tumors aggressiveness

We determined whether alterations in the expression of p53, p16 INK4 and p21 WAF1/CIP1 influence the invasiveness of a subset of gastric adenocarcinomas co-expressing TGFα and EGFR. Immunopositivity for TGFα-EGFR (26%) was observed in both early and advanced adenocarcinomas, and 88% of these showed immunoreactivity for p53. SSCP analysis revealed that in 81% of these tumors the p53 gene was mutated in exons 5–8. The intensity of p53 immunoreactivity was significantly higher ( P <0.013) in deeply invasive tumors. p16 INK4 and p21 WAF1/CIP1 immunoreactivity was detected in 93 and 76% of the samples co-expressing TGFα-EGFR but the levels were not correlated with those of p53 and other clinico-pathological parameters. We conclude that gastric adenocarcinomas potentially dependent upon the TGFα-EGFR autocrine loop for growing exhibit increased aggressiveness in the presence of aberrant p53.

Association of p53 tumor suppressor gene with paraclinical and clinical modalities of gliomas patients in Malaysia.

Alteration of the tumor suppressor gene p53 is considered to be a critical step in the development of human cancer. Changes in this gene have been detected in a wide range of human tumours, including gliomas. In glioma, the presence of p53 gene alterations has been associated with worse prognosis. Forty-seven Malaysian adult glioma patients of the Malay race were prospectively studied over a period of 3 years where the presence of p53 mutation using cold-SSCP method and their clinical and paraclinical response were correlated. Among these glioma patients, p53 mutations were detected in 12 tumors, an incidence rate of 25.5%. Mutations were found in 2 patients of grade II, and 5 patients both in grade III and grade IV. The sequencing results revealed the presence of base-substitutions (7) (58.3%) and frameshifts mutations (5) (41.7%). Of the base-substitutions, 57.1% were transversions and 42.9% were transitions. Our analysis shows that 3 factors were associated with p53 mutations i.e. grade, site and consistency of tumour using univariate analysis although multivariate analysis revealed no positive on predictors of mutation. In conclusion, although p53 genetic alterations are involved in glioma patients in Malaysia, it has no impact on prognosis.

P53 gene status and expression of p53, MDM2, and p14 proteins in ameloblastomas.

To clarify the roles of the p53-MDM2-p14(ARF) cell cycle regulation system in oncogenesis and cytodifferentiation of odontogenic tumors, p53 gene status and expression of p53, MDM2, and p14(ARF) proteins was analyzed in ameloblastomas as well as tooth germs. Paraffin sections of 16 tooth germs and 46 benign and 5 malignant ameloblastomas were examined immunohistochemically for the expression of p53, MDM2, and p14(ARF) proteins. Frozen tissue samples of 10 benign ameloblastomas and 1 malignant (metastasizing) ameloblastoma were analyzed by direct DNA sequencing to detect p53 gene alteration. Immunohistochemical reactivity for p53 was detected in 2 of 13 tooth germs, 13 of 29 ameloblastomas, and 5 of 5 malignant ameloblastomas, and the expression ratio of p53 in tooth germs was significantly lower than those in benign and malignant ameloblastomas. Direct DNA sequencing showed no alteration of p53 gene exons 5-8 in any sample of 10 benign ameloblastomas and 1 metastasizing ameloblastoma. Expression of MDM2 and p14(ARF) was detected in all samples of normal and neoplastic odontogenic epithelium, and the expression ratios in tooth germs tended to be lower than those in benign and malignant ameloblastomas. In ameloblastomas, expression of p53, MDM2, and p14(ARF) was significantly higher in plexiform cases than in follicular cases. Markedly decreased reactivity for p53, MDM2, and p14(ARF) was detected in keratinizing and granular cells in ameloblastoma subtypes. Basal cell ameloblastoma showed slightly higher reactivity for p53, MDM2, and p14(ARF) as compared with other subtypes. Elevated expression of p53, MDM2, and p14(ARF) in benign and malignant ameloblastomas suggests that alteration of the p53-MDM2-p14(ARF) cascade is involved in oncogenesis and/of malignant transformation of odontogenic epithelium. p53 gene status implied that p53 mutation might play a minor role in neoplastic changes of odontogenic epithelium. Immunoreactivity for p53, MDM2, and p14(ARF) in ameloblastoma variants suggests that these factors might be associated with tissue structuring and cytodifferentiation of ameloblastomas.

Possible distinct molecular carcinogenic pathways for bladder cancer in Ukraine, before and after the Chernobyl disaster

After the Chernobyl accident in 1986, the incidence of urinary bladder cancers in the Ukraine increased gradually from 26.2 to 43.3 per 100,000 people between 1986 and 2001. In the areas of low level but persistent cesium-137 (137Cs) radio-contamination, a unique atypical radiation-related urinary bladder cystitis named 'Chernobyl cystitis', a possible pre-neoplastic condition in humans, has been detected. We have previously documented high incidences of bladder lesions, including severe dysplasias and/or carcinoma in situ, in association with this cystitis and correlating with oxidative DNA damage. To further investigate the molecular mechanisms underlying bladder carcinogenesis with this specific etiology, mutation analysis of p53 gene (exon 5-8) was performed for 11 and 18 paraffin-embedded bladder cancers in Ukrainians, respectively collected before and after the Chernobyl disaster. DNAs were extracted and subjected to nested PCR-single-strand conformational polymorphism analysis followed by direct DNA sequencing, as well as p53 immunohistochemistry (IHC). The incidences of p53 gene mutation were 54.5 and 16.7% for before and after the Chernobyl disaster, respectively, the difference being statistically significant. Also a tendency for higher p53 IHC score was apparent in the earlier group of lesions. No significant difference was noted for the proportions of historical types. These results point to possible distinct molecular carcinogenic pathways of bladder cancer formation, before and after the Chernobyl disaster, on the basis of variation in p53 gene alteration.

Alterations of p16 and prognosis in biliary tract cancers from a population-based study in China.

Biliary tract cancer is an uncommon malignancy with a poor survival rate. We evaluated p16 gene alteration as a prognostic marker for this disease. We studied p16 gene alterations by sequencing, methylation, and loss of heterozygosity of chromosome 9p in 118 biliary tract carcinomas, including 68 gallbladder cancers, 33 extrahepatic bile duct cancers, and 17 ampullary cancers. Survival was evaluated in 57 patients with gallbladder carcinomas, 27 with bile duct carcinomas, and 16 with ampullary carcinomas with and without somatic p16 alterations detected by two different methods. p16 gene alterations including silent mutations were present in 61.8% gallbladder cancers, 54.5% bile duct cancers, and 70.6% ampullary cancers. p16 gene nonsilent mutations, p16 methylation, and loss of chromosome 9p21-22 that targets p14, p15, and p16 genes were present in 13 of 53 (24.5%), 8 of 54 (14.8%), and 32 of 44 (72.7%) gallbladder tumors; 5 of 25 (20.0%), 5 of 31 (16.1%), and 12 of 21 (57.1%) bile duct tumors; and 3 of 13 (23.1%), 6 of 15 (40.0%), and 8 of 16 (50.0%) ampullary tumors, respectively. The mean survival of patients with gallbladder cancers without p16 alterations was 21.5 +/- 14.8 months compared with 12.1 +/- 11.4 months for patients with p16 alterations (P = 0.02). Alteration of p16 gene alone or in combination with alterations of other tumor suppressor genes on chromosome 9p is a prognostic indicator in gallbladder carcinoma, with more favorable survival rates associated with carcinomas lacking p16 gene alterations.

Alterations of p53 gene and microsatellite instability in ulcerative colitis and ulcerative colitis-associated colorectal cancer

To study the expression of p53 protein, incidence of p53 gene mutation and microsatellite instability in ulcerative colitis, dysplasia of colonic mucosa and ulcerative colitis-associated colorectal cancer. P53 protein expression was detected by immunohistochemistry in 70 specimens from 21 cases of ulcerative colitis and 25 colonic mucosa specimens from normal subjects. The specimens of ulcerative colitis were examined for the mutation in exon 5, 6, 7, 8 of p53 gene with microdissection-PCR-SSCP/HA-clone-sequencing technique and the alterations in 10 microsatellite loci with microdissection-PCR-SSLP-clone- sequencing technique. None of 25 normal specimens was p53-positive immunohistochemically, while 4/21 of ulcerative colitis specimens were p53-positive. P53- positive rate in inflammatory mucosa of ulcerative colitis specimens was 0/5, while that was 1/7, 2/7 and 1/2 in low-grade displasia (LGD), high-grade displasia (HGD) and carcinoma, respectively. The abnormal exons were detected by SSCP and confirmed by sequencing in 2 out of 21 cases: one was exon 6 in a case with carcinoma and the other was exon 8 in a HGD case; both had positive P53 expression. Two cases showed positive in Bat26 locus by SSLP: one was a LGD case, the other was a case of carcinoma, who also had abnormal exon 6 of p53 gene. Other 9 microsatellite loci, (TGF beta RII(A)(10), IGFIIR(G)(8), IGFIIR(CT)(5), TGF beta RII(GT)(3), BAX(G)(8), hMSH3(A)8, hMSH6(C)(8), TCF4(A)(9) and DPC4 (CA)(17)) were showed negative in all cases. P53 gene mutations and microsatellite instability may be one of the mechanisms for higher risk of carcinogenesis in ulcerative colitis.

Evaluation of oligonucleotide arrays for sequencing of the p53 gene in DNA from formalin-fixed, paraffin-embedded breast cancer specimens.

Routine tissue processing has generated banks of paraffin-embedded tissue that could be used in retrospective cohort studies to study the molecular changes that occur during cancer development. The purpose of this study was to determine whether a p53 microarray could be used to sequence the p53 gene in DNA extracted from formalin-fixed, paraffin-embedded (FFPE) tissues. DNA was extracted from 70 FFPE breast cancer tissue specimens. p53 was sequenced with an oligonucleotide microarray (p53 GeneChip; Affymetrix), and the results were compared with the results obtained from direct sequencing. DNA was extracted from 62 of 70 cases. We identified 26 mutations in 24 of the 62 cases by the p53 GeneChip. No polymorphisms were detected, and exon 4 could not be evaluated in 20 cases. There were 43 genetic alterations detected by direct sequencing in 35 of the 62 cases. These consisted of 26 polymorphisms and 17 mutations in exons or splice sites. Fifteen mutations were identified by both methods. Direct sequencing detected significantly more gene alterations (43 of 54) in DNA extracted from FFPE tissue than the p53 GeneChip (26 of 54; P = 0.018). However, if the changes in exon 4 were eliminated from this comparison, the p53 GeneChip detected 26 of 27 mutations compared with direct sequencing, which identified 16 of 27 mutations. (P = 0.016). A combination of oligonucleotide microarray and direct sequencing may be necessary to accurately identify p53 gene alterations in FFPE breast cancer. The p53 GeneChip cannot be used to detect exon 4 polymorphisms (codon 72) in FFPE breast cancer tissue.

High frequency of G/C transversion on p53 gene alterations in breast cancers from Taiwan

p53 gene mutation is a very frequent event in many human cancers and is associated with a poor clinical outcome in breast cancer patients. Analysis of p53 gene mutations can also provide clues to the etiology of tumor formation. The present study was conducted to investigate the p53 mutations in patients with breast cancer from Taiwan. Tumor samples from 119 patients undergoing mastectomy for breast cancer were evaluated. The mutational status of the p53 gene (exons 5–8) was screened by polymerase chain reaction-single strand conformation polymorphism analysis followed by direct sequencing. Of all 119 cases of breast carcinoma, 26 mutations of the p53 gene were found in 22 cases (18.5%). Among these mutations, 78% (20/26) were point mutations with the majority of those being missense mutations (75%, 15 of 20 mutations) and the other 22% (6/26) were frameshift mutations. No significant correlation between p53 mutations and clinicopathological features was found, including HER2 status. Moreover, our results disclosed distinct mutation spectra in excess transversions to transitions (15/21, 71.4% vs. 6/21, 28.6%) with GC to CG dominant (6/15, 40%). Mutation hot spots we identified at codons 167, 185, 186, 210, 265 and 295 have rarely been documented in the literature. These findings showed that p53 gene mutation might contribute to the pathogenesis of breast carcinoma. Furthermore, the different mutation spectrum with high transversions in G:C to C:G may imply that the exogenous mutagens outweigh the endogenous processes in breast cancer in patients in Taiwan.

Regulation of telomerase and its hTERT messenger in colorectal cancer

Telomeres are the distal ends of human chromosomes composed of tandem repeats of the sequence TTAGGG. In most human somatic cells, telomerase activity is undetectable, and the telomere length is progressively shortened during cell proliferation, leading to cellular senescence. In contrast, telomerase is activated in the vast majority of cancer cells, including colorectal cancer. The human telomerase complex is comprised of multiple components, but telomerase reverse transcriptase (hTERT) is the most important component for the control of telomerase activity. The p53 protein is a transcription factor with multiple biological activities, including cell cycle arrest and/or apoptosis upon DNA damage, hypoxia and oncogene activation; this requires transactivation or repression of specific target genes by wild-type p53. To better understand if a link between hTERT/telomerase regulation and p53 status exists in colorectal carcinogenesis, we analysed 43 cases of colorectal carcinoma for hTERT mRNA expression and telomerase activity. Moreover, a complete analysis of p53 status was performed. Alterations of p53 gene were found in 44.19% of cases and missense point mutations represented a high proportion of p53. Both telomerase activity (p=0.014) and hTERT expression (p=0.03) were significantly associated with p53 mutations, suggesting a role of p53 in the signaling pathway for telomerase control.

P53 and Rb tumor suppressor gene alterations in gastric cancer.

Inactivation of tumor suppressor genes has been frequently observed in gastric carcinogenesis. Our purpose was to study the involvement of p53, APC, DCC, and Rb genes in gastric carcinoma. Loss of heterozygosity of the p53, APC, DCC and Rb genes was studied in 22 gastric cancer tissues using polymerase chain reaction; single-strand conformation polymorphism of the p53 gene exons 5-6 and exons 7-8 was studied using 35S-dATP, and p53 expression was detected using a histological immunoperoxidase method with an anti-p53 clone. No loss of heterozygosity was observed in any of these tumor suppressor genes; homozygous deletion was detected in the Rb gene in 23% (3/13) of the cases of intestinal-type gastric carcinoma. Eighteen (81.8%) cases showed band mobility shifts in exons 5-6 and/or 7-8 of the p53 gene. The presence of the p53 protein was positive in gastric cancer cells in 14 cases (63.6%). Normal gastric mucosa showed negative staining for p53; thus, the immunoreactivity was likely to represent mutant forms. The correlation of band mobility shift and the immunoreactivity to anti-p53 was not significant (P =.90). There was no correlation of gene alterations with the disease severity. The inactivation of Rb and p53 genes is involved in gastric carcinogenesis in our environment. Loss of the Rb gene observed only in the intestinal-type gastric cancer should be further evaluated in association with Helicobacter pylori infection. The p53 gene was affected in both intestinal and diffuse histological types of gastric cancer.

Pretreatment p53 nuclear overexpression as a prognostic marker in superficial bladder cancer treated with Bacillus Calmette-Guérin (BCG).

Altered p53 gene product correlates with the stage and grade of bladder tumor, but its value as a predictor of BCG response has been disappointing. In order to revisit the prognostic value of pretreatment p53 nuclear overexpression for the BCG response, we studied a large cohort of consecutive patients with superficial bladder cancer treated with BCG. From 1988 to 2001, 102 patients with a history of multifocal, recurrent, and/or high-risk papillary transitional cell carcinoma or carcinoma in situ, were treated for the first time with BCG. p53 immunostaining was performed on paraffin-embedded tissues using monoclonal antibody DO7 and an automated immunostainer. Special attention was paid to the conditions of tumor fixation. p53 overexpression was defined as more than 20% tumor cells with p53-stained nuclei. Immunostaining was significantly higher for Ta/T1 G3 +/- Cis (p < 0.001), tumoral substage T1b (p = 0.001), grade 3 (p = 0.0001), and Cis (p = 0.002). Times to recurrence, progression and cancer death were shorter among patients with p53 overexpression (p = 0.03; p < 0.0001; p = 0.0003). In multivariate analysis, p53 overexpression was an independent predictor of recurrence (p = 0.0003) [RR = 0.15; 95%CI, 0.06 to 0.42]. Pretreatment p53 nuclear overexpression in superficial bladder tumors is associated with a high risk of disease recurrence, progression and cancer death after BCG therapy. Applying antibody DO7 with an automated immunostainer and stringent fixative conditions, p53 nuclear immunostaining yields clinically relevant information and may be a useful tool for selecting patients with superficial bladder cancer who might be resistant to BCG.

Dedifferentiated Adenoid Cystic Carcinoma: A Clinicopathologic Study of 6 Cases

Dedifferentiated adenoid cystic carcinomas are a recently defined, rare variant of adenoid cystic carcinomas characterized histologically by two components: conventional low-grade adenoid cystic carcinoma and high-grade “dedifferentiated” carcinoma. We examined six cases and analyzed their clinicopathologic profiles, including immunohistochemical features and p53 gene alterations. The 6 patients (3 men and 3 women) had a mean age of 46.8 years (range, 34–70 y). The mean size of the tumors was 3.5 cm (range, 1.7–6 cm). The submandibular gland, maxillary sinus, and nasal cavity were involved in 2 cases each. Postoperatively, 5 patients had local recurrence and 5 developed metastatic disease. Five patients died of disease at a mean of 33.7 months after diagnosis (range, 6–69 mo), and one other was alive with disease at 60 months. Histologically, the conventional low-grade adenoid cystic carcinoma component of the tumors consisted of a mixture of cribriform and tubular patterns with scant solid areas. The high-grade dedifferentiated carcinoma component was either a poorly differentiated adenocarcinoma (4 cases) or undifferentiated carcinoma (2 cases). Three tumors were studied immunohistochemically. Myoepithelial markers were expressed in low-grade adenoid cystic carcinoma but not in the dedifferentiated component. In 2 cases, diffusely positive p53 immunoreactivity together with HER-2/neu overexpression was restricted to the dedifferentiated component. Loss of pRb expression was demonstrated only in the dedifferentiated component of the 1 other case. The Ki-67–labeling index was higher in the dedifferentiated component than in the low-grade adenoid cystic carcinoma component. Furthermore, molecular analysis of 2 cases demonstrated the loss of heterozygosity at p53 microsatellite loci, accompanied by p53 gene point mutation, only in the dedifferentiated carcinoma component of 1 case, which was positive for p53 immunostaining. These results indicate that dedifferentiated adenoid cystic carcinoma is a highly aggressive tumor. Because of frequent recurrence and metastasis, the clinical course is short, similar to that of adenoid cystic carcinomas with a predominant solid growth pattern. Limited evidence suggests that p53 abnormalities in combination with HER-2/neu overexpression or loss of pRb expression may have a role in dedifferentiation of adenoid cystic carcinoma.