Molecular and pathological basis of HPV-negative cervical adenocarcinoma seen in a global study

International surveys find HPV-negativity in up to 30% of cervical adenocarcinomas. We investigated the pathological diagnosis by expert consensus with immunohistochemistry and the presence of somatic mutations in recognised tumour genes in HPV-positive and negative cervical adenocarcinomas (CADC). A sample was selected of 45 paraffin-embedded cervical blocks diagnosed locally as usual cervical adenocarcinoma from a global study. These represented different diagnoses made at previous diagnostic review and HPV status. All were suitable for analysis for somatic tumour associated gene mutations. Three pathologists examined H/E slides and immunohistochemistry for p16, progesterone receptor and p53 and classified the cases. L1 genes from high-risk HPVs and low-risk HPVs were analysed by SPF10 PCR-DEIA-LiPA25 version 1 in whole tissue sections and microdissected tumour and retested by PCR for E6/E7 genes of hrHPVs if negative. Cases were analysed for microsatellite instability and next-generation sequencing mutation analysis. From the 45 cases, 20 cases of usual CADC were confirmed of which 17 (85%) were HPV-positive in tumour cells. The other 25 cases were reclassified as endometrial, serous, clear-cell and gastric-type adenocarcinomas and all were HPV-negative in tumour cells. Careful retesting for HPV DNA and IHC leads to more accurate identification of HPV-positive usual cervical adenocarcinomas. Endometrioid endometrial adenocarcinomas, other uterine adenocarcinoma with multiple somatic mutations were important in misclassification of HPV-negative cases locally managed as cervical adenocarcinoma, as was gastric-type adenocarcinoma with germline STK11 mutation in East Asia. Few consensuses confirmed HPV-negative usual cervical adenocarcinomas showed somatic tumorigenic mutations also seen in some HPV-positive usual CADC.     

Immunohistochemical analysis of p53 in vulval intraepithelial neoplasia and vulval squamous cell carcinoma

Human papillomavirus (HPV) is thought to cause some vulval squamous cell carcinomas (VSCC) by degrading p53 product. Evidence on whether HPV-negative VSCC results from p53 mutation is conflicting. We performed immunohistochemistry for p53 product on 52 cases of lone vulval intraepithelial neoplasia (VIN), 21 cases of VIN with concurrent VSCC and 67 cases of VSCC. We had previously performed HPV detection and loss of heterozygosity (LOH) analyses on these samples. Abnormal p53 immunoreactivity (p53-positive) rates in HPV-positive VSCC and HPV-negative VSCC were 22% (12/54) and 31% (4/13), respectively (P<0.74). p53 immunoreactivity was associated with LOH at the p53 locus (P<0.004), but neither technique differentiated between HPV-positive and HPV-negative VSCC. p53 immunoreactivity was associated with overall LOH rates (p53-positive VSCC vs p53-negative VSCC mean fractional regional allelic loss 0.41 vs 0.24, respectively, P<0.027). LOH at 3p25 was more frequent in p53-positive VSCC cf p53-negative VSCC (70 vs 21%, respectively, P<0.007). There was a trend in p53 disruption associated with invasive disease; HPV-positive VSCC demonstrated more disruption than VIN associated with VSCC, which had more disruption than lone VIN III (22 vs 10 vs 0%, respectively, P<0.005). In all, three out of 73 cases of VIN were p53-positive. All three were associated with concurrent or previous VSCC. Meta-analysis of previous studies revealed significantly more p53 disruption in HPV-negative VSCC cf HPV-positive VSCC (58 vs 33%, respectively; P<0.0001). p53 immunoreactivity/mutation in VIN only appeared in association with VSCC. These data suggest that HPV-independent vulval carcinogenesis does not exclusively require disruption of p53, p53 disruption may work synergistically with LOH at specific loci and p53-positive VIN should be checked carefully for the presence of occult invasion.     

The role of p53 inactivation in human cervical cell carcinoma development.

We investigated the association between human papillomavirus (HPV) infection and p53 gene mutation in 47 primary uterine cervical cancers. HPV DNA sequences were present in 43 cancers (91.5%), and one of these cancers contained a p53 gene mutation. In addition, one of the remaining four HPV-negative cancers also contained a p53 gene mutation. As a result, p53 inactivation corresponded to the development of 44 of the primary uterine cervical cancers studied (93.6%). We obtained both primary and recurrent tumours from four cases. In two of these cases, the HPV genomes that were present in an episomal state in the primary tumours were observed to have disappeared in the recurrent tumours. One of these recurrent tumours also contained a p53 gene mutation, which suggested the possibility that p53 inactivation was required in order to maintain the aggressive behaviour in this cancer either by an HPV infection or by a p53 gene mutation. No MDM2 gene amplification was observed in the tumours that carried neither HPV DNAs nor p53 gene mutations.     

The carcinogenic role of oncogenic HPV and p53 gene mutation in cervical adenocarcinomas

Thirty tumors were collected from our archive of cervical adenocarcinomas. They were examined with respect to the content of oncogenic HPV and presence of mutations in the p53 gene exons 5 through 8. Furthermore, available clinical information on the cases was reviewed. For the detection of p53 gene and presence of oncogenic HPV, PCR followed by direct sequence analysis of the amplified DNA was employed. Seventeen tumors were identified as HPV-positive, comprising both HPV types 18 and 16. Six cases showed a p53 gene mutation, of which five were of the missence and one of the silent type. No statistical correlation between the occurrence of oncogenic HPV and presence of p53 gene mutation (p=0.67) was recorded. Among the tumors with p53 gene mutation, three were HPV-positive and three were HPV-negative. The determination of p53 gene mutations was not related to clinical findings such as the stage of the tumor or presence of metastases of the lymph nodes. However, p53 gene mutations were somewhat more prevalent in low differentiated tumors (p<0.02). The results indicate that oncogenic HPV and p53 gene mutations have independent carcinogenic roles in cervical adenocarcinomas.     

HPV感染与p53蛋白及P-糖蛋白表达在非小细胞肺癌中的关系及其临床意义

目的:探讨人乳头瘤病毒(humanpapillomavirus,HPV)感染在非小细胞肺癌(nonsmallcelllungcancer,NSCLC)发生中的病因学意义及其与p53蛋白和P糖蛋白(Pgp)表达之间的相关性。方法:应用PCR、免疫组化方法分别检测76例NSCLC组织中HPVDNA及其E6、E7原癌蛋白、p53蛋白和Pgp的表达情况。结果:NSCLC中HPVDNA及其E6、E7原癌蛋白的检出率分别为40.8%(31/76)、43.4%(33/76),2种检测方法的符合率为78.9%(60/76);p53蛋白和Pgp的阳性率分别为63.2%(48/76)、59.2%(45/76),且HPV感染阳性组中p53蛋白的表达率为80.6%(25/31),显著高于阴性组51.1%(23/45)(P<0.05);p53蛋白表达阳性组中Pgp的表达率为68.8%(33/48),显著高于阴性组42.9%(12/28)(P<0.05);而HPV感染阳性组与阴性组间Pgp的表达无显著性差异(P>0.05)。HPV感染与高、中分化程度的NSCLC及吸烟有关。结论:HPV感染可能是NSCLC发生的另一重要病因学因素,且HPV感染可能导致p53基因突变,后者可能促进肺癌耐药性的增加。     

Elderly Japanese women with cervical carcinoma show higher proportions of both intermediate-risk human papillomavirus types and p53 mutations

The p53 mutation has been found only in 0-6% of cervical carcinomas. In light of recent studies demonstrating that mutation of p53 gene was found in over 20% of the patients with vulvar carcinoma, a disease of elderly women and a known human papillomavirus (HPV)-related malignancy, we analysed mutation of the p53 gene in 46 women with cervical carcinomas at the age of 60 or more (mean; 71 years, range; 60-96 years). The presence of HPV and its type were analysed by polymerase chain reaction (PCR)-based assay using the consensus primers for L1 region. Mutation of the p53 gene was analysed by PCR-based single-strand conformation polymorphism and DNA sequencing technique. Point mutation of the p53 gene was detected in 5 out of 46 (11%) cervical carcinomas: 1 of 17 (6%) samples associated with high-risk HPVs (HPV 16 and HPV 18) and 4 of 27 samples (15%) with intermediate-risk HPVs (P= 0.36) whereas no mutation was found in 2 HPV negative cases. The mutated residues resided in the selective sequence known as a DNA-binding domain. The immunohistochemistry revealed the overexpression in cancer tissues positive for p53 mutation. All of the observed mutations of the p53 gene were transition type, suggesting that the mutation may be caused by endogenous mutagenesis. Although falling short of statistical significance reduces the strength of the conclusion, data presented here imply that p53 gene mutation, particularly along with intermediate-risk HPV types, may constitute one pathogenetic factor in cervical carcinoma affecting elderly women.     

p53 mutations in relation to human papillomavirus type 16 infection in squamous cell carcinomas of the head and neck

The relationship between human papillomavirus (HPV) type 16 infection and p53 gene mutations was investigated in squamous cell carcinomas of the head and neck (SCCHN). HPV was detected by general primer-mediated and type-specific PCR. Alterations in the p53 gene were investigated using single-strand conformation polymorphism and sequence analysis in 27 SCCHN, of which 12 were HPV 16-positive and 15 were HPV-negative. Mutations were detected in 2/12 (16.7%) HPV 16-positive and 7/15 (46.7%) HPV-negative tumours; this difference was not statistically significant. The predominant mutations were deletions and C → T transitions; G → T transversions were found in only 2 tumours. Our results indicate that the presence of HPV 16 and p53 mutations is not mutually exclusive and detection of a p53 mutation does not exclude a potential role for HPV 16 in the pathogenesis of a subset of SCCHN. Int. J. Cancer 71: 796-799, 1997. © 1997 Wiley-Liss Inc.     

Human papillomavirus DNA and p53 status in penile carcinomas

Our study aimed at evaluating the presence of human papillomavirus (HPV) DNA in a series of 84 paraffin-embedded (PET) penile carcinomas. We have also investigated the presence of p53 mutations in these tumors by immunohistochemistry (IHC), single-stranded conformational polymorphism (SSCP) and DNA sequencing. Tissues were submitted to amplification of a 268 bp fragment from the β-globin gene and a fragment of the E6 gene of HPV types 6, 11, 16 and 18. Twenty samples (18 fixed in Bouin's solution and 2 in buffered formalin) were found inadequate and were excluded from the analysis. In the remaining 64 tumors, HPV DNA was found in 26% of the samples. The prevalence of HPV in fresh samples of the same tumors was 56%. The most prevalent type was HPV 16 in both fresh samples and PET. Isotopic in situ hybridization was performed in all PET samples, but only 2 cases were positive, 1 for HPV 16 and 1 for HPV 18. Immunohistochemistry with anti-p53 pAb1801 antibody showed a positive nuclear reaction over more than 5% of tumor cells in 26% of the cases. SSCP of exons 5–8 of the p53 gene was performed on 9 HPV-positive and 12 HPV-negative specimens. Abnormal mobility was found in 26% of the tumors, of which 2 were HPV positive and 5 HPV negative. Point mutations were detected in p53 exons 6 (1 case), 7 (1 case) and 8 (5 cases), showing that high-risk type HPVs and mutated p53 may coexist in these tumors. Our data indicate that a subset of penile carcinomas are etiologically related to HPV and that an overlapping subset may arise from mutational events in the p53 gene. Int. J. Cancer76:779–783, 1998.© 1998 Wiley-Liss, Inc.     

p53 mutations in cervical carcinogenesis--low frequency and lack of correlation with human papillomavirus status.

p53 gene aberrations are common in human malignancies, and recent studies suggest that in cervical carcinoma p53 function is inactivated either by complex formation with human papillomavirus (HPV) E6 product or by gene mutation. Using polymerase chain reaction (PCR) followed by denaturing gradient gel electrophoresis (DGGE), we examined the mutational status of the four ''hotspot'' regions of the p53 gene in 47 primary cervical carcinomas. HPV status was determined, also by PCR. In 20 of these cases, we examined for loss of heterozygosity (LOH) on chromosome 17p13. In the 47 carcinomas, and in a further 68 biopsy specimens from normal, premalignant and malignant cervix, we investigated aberrant immunocytochemical expression of p53. Immunocytochemically, abnormal p53 expression was detected in 13 of 115 cases (8/57 carcinomas). Somatic mutation in p53 was detected in 1 of 47 cervical carcinomas; 36 were positive for HPV 16, 18 or 33. A low level of allele loss (3 out of 20 cases) was detected on chromosome 17p, occurring in both HPV-positive and HPV-negative cases, and in cases with and without p53 mutations. We conclude that somatic mutation in the hotspot regions of the p53 gene occurs infrequently in cervical carcinomas; that immunocytochemically detectable levels of p53 are also infrequent; and that there is no consistent correlation between p53 mutational status, LOH on chromosome 17p or HPV status in these cancers.     

人乳头瘤病毒感染和p53基因突变与宫颈癌的关系

目的：探讨人乳头瘤病毒１６ 和１８ 型及抑癌基因ｐ５３ 突变对宫颈的致癌作用以及 Ｈ Ｐ Ｖ 感染与ｐ５３ 基因突变的相关性。方法：采用聚合酶链反应（ Ｐ Ｃ Ｒ） 技术和限制性酶切片段多态性分析（ Ｒ Ｆ Ｌ Ｐ） 技术对３４ 例原发性宫颈癌组织及３０ 例正常宫颈组织 Ｈ Ｐ Ｖ１６ ,１８ 型 Ｄ Ｎ Ａ 及抑癌基因ｐ５３ 的突变进行了检测。结果： Ｈ Ｐ Ｖ１６ ,１８ Ｄ Ｎ Ａ 在宫颈癌的总阳性率为６４７ ％ （２２／３４） ,正常宫颈组织只有６７ ％ 阳性,８例宫颈癌组织出现ｐ５３ 基因第６ 外显子突变,其中２ 例为 Ｈ Ｐ Ｖ１６ Ｄ Ｎ Ａ 阳性、１ 例 Ｈ Ｐ Ｖ１８ Ｄ Ｎ Ａ 阳性。结论：宫颈癌的发病与 Ｈ Ｐ Ｖ 感染及ｐ５３ 基因突变有关,宫颈癌组织中ｐ５３ 基因突变与 Ｈ Ｐ Ｖ 感染无关。     

Relationship among human papillomavirus infection, p16(INK4a), p53 and NF-κB activation in penile cancer from northern Thailand

Human papillomavirus (HPV) E6 and E7 oncoproteins are essential factors for HPV oncogenesis. These E6 and E7 gene products play a central role in the induction of malignant transformation by interacting with several cellular regulatory proteins such as p16(INK4a), p53 and nuclear factor κB (NF-κB). In the present study, conducted in northern Thailand, HPV-DNA was detected in penile cancer cases using an in situ hybridization procedure and p16(INK4a), p53 and NF-κB were detected by immunohistochemistry. Using the cell cycle regulatory proteins p16(INK4a) (61.5%) and p53 (71.8%), it was found that of the 51 cases, 39 (76.5%) were HPV-DNA-positive in penile cancer. On the other hand, 25% p16(INK4a) and 75% p53, respectively, were found in HPV-negative cases. Prevalence of HPV infection (76.5%) was shown in penile cancer cases in northern Thailand. No difference was found between HPV-positive and HPV-negative cases with respect to the presence of the cell cycle regulatory protein p53. On the other hand, p16(INK4a) was found to be different between HPV-positive and HPV-negative cases. Inactivation of tumor suppressor genes, such as p16(INK4a) and p53, to genetic instability, cell immortalization, accumulation of mutations and cancer formation, with or without HPV and irrespective of HPV infection, is therefore suggested. Of the 39 HPV-positive cases, 35 (89.7%) were NF-κB-positive in the nucleus, 29 (74.4%) in the cytoplasm and 37 (94.9%) in the nucleus and/or cytoplasm. NF-κB was detected in 4 (33.3%) of the 12 HPV-negative cases. Therefore, we propose that penile cancer cases with HPV infection are more likely to activate NF-κB than those without HPV infection.     

Comparative genomic hybridization analysis of tonsillar cancer reveals a different pattern of genomic imbalances in human papillomavirus-positive and -negative tumors

Our aim was to map and compare genomic imbalances in human papillomavirus (HPV)-positive and -negative squamous cell carcinomas of the tonsil. Twenty-five primary carcinomas were analyzed by comparative genomic hybridization. Fifteen (60%) were found to be HPV-positive by PCR, and the majority were HPV-16. There were statistically significant differences in the distribution of DNA gains and losses between the HPV-positive and -negative samples. Eleven of 15 HPV-positive samples (73%) showed gain on chromosome 3q24-qter, while only 4/10 (40%) HPV-negative samples had the same gain (p = 0.049). Furthermore, 4/10 (40%) HPV-negative samples but no HPV-positive samples had gain on chromosome 7q11.2-q22 (p = 0.017). As expected, and similar to previous studies, patients with an HPV-positive tumor had a statistically significantly better disease-specific survival than patients with an HPV-negative tumor (p = 0.002). The most common changes, e.g., gain on 3q or 8q, loss on 11q or 13 and loss on chromosome 7q in HPV-negative tumors, did not have any influence on prognosis. However the number of cases in each subgroup was limited.     

Alterations of the p53 gene in human primary cervical carcinoma with and without human papillomavirus infection.

A previous report using cervical carcinoma cell lines suggests that the inactivation of two tumor suppressor gene products, p53 and pRB, either by complex formation with the E6 and E7 proteins of oncogenic human papillomaviruses (HPVs) or by mutation, may be an important step in cervical carcinogenesis (M. Scheffner et al., Proc. Natl. Acad. Sci. USA, 88: 5523-5527, 1991). The present study was designed to clarify the association between p53 inactivation and infection with oncogenic HPVs in primary carcinomas of human uterine cervix. We examined 36 primary cervical carcinomas for the presence of HPV DNAs by Southern blot analysis with probes specific for HPV-16, -18, -31, -33, -52, -56, and -58. HPV DNA sequences were detected in 19 of 36 tumors: 10 cases with HPV-16; 3 cases with -18; 3 cases with -58; 2 cases with -56; and one case with -52. The presence of HPV-16 and -18 in cervical carcinomas was further reexamined using polymerase chain reaction. HPV DNA sequences were detected in an additional 10 cases: 9 cases with -16 and one case with -18. The inactivation of the p53 gene by allelic loss or by point mutation was also examined. No allelic loss at the polymorphic site in codon 72 of the p53 gene was detected in any of 10 informative cases. Missense point mutations in the highly conserved regions of the p53 gene were demonstrable as single-stranded conformational polymorphisms of polymerase chain reaction-amplified DNA fragments and subsequently identified by direct DNA sequencing. Point mutations were detected in only two cases: one with an ATG----CTG transversion in codon 133 of exon 5, resulting in a Met----Leu substitution, and another with a CGG----TGG transition in codon 248 of exon 7, resulting in an Arg----Trp substitution. Both tumors with point mutations in p53 genes were among 10 tumors which contained a small copy number of HPV-16 DNA sequences (1 copy of HPV/10(1) to 10(5) cells) detectable by polymerase chain reaction amplification but not by Southern blot analysis of genomic DNAs derived from the tumors. None of 19 tumors with a large copy number of HPV DNA sequences detectable by Southern blot analysis (more than 1 copy of HPV/2 to 10 cells) nor any of 7 tumors with undetectable HPV DNA sequences contained p53 gene mutations in the regions examined.(ABSTRACT TRUNCATED AT 400 WORDS)     

Inverse relationship between human papillomavirus-16 infection and disruptive p53 gene mutations in squamous cell carcinoma of the head and neck.

PURPOSE: Squamous cell carcinomas of the head and neck (HNSCC) often harbor p53 mutations, but p53 protein degradation by the viral oncoprotein E6 may supercede p53 mutations in human papillomavirus 16 (HPV16)-positive tumors. The prevalence of p53 mutations in HPV-positive HNSCCs is indeed lower, but in some tumors these alterations coexist. The purpose of this study was to discern whether HNSCCs differ in the type of p53 mutations as a function of HPV16 status. EXPERIMENTAL DESIGN: The study was nested within a prospective multicenter study (ECOGE 4393/RTOG R9614) of patients with HNSCC treated surgically with curative intent. Tumors from one study center were used to construct a tissue microarray. The tumors were well characterized with respect to p53 mutational status. The tissue microarray was evaluated by HPV16 in situ hybridization. HPV16 analysis was also done on a select group of tonsillar carcinomas known to harbor disruptive p53 mutations defined as stop mutations or nonconservative mutations within the DNA binding domain. RESULTS: HPV16 was detected in 12 of 89 (13%) HNSCCs. By tumor site, HPV16 was detected in 12 of 21 (57%) tumors from the palatine/lingual tonsils, but in none of 68 tumors from nontonsillar sites (P < 0.00001). Both HPV16-positive and HPV16-negative HNSCCs harbored p53 mutations (25% versus 52%), but disruptive mutations were only encountered in HPV16-negative carcinomas. Of seven tonsillar carcinomas with disruptive p53 mutations, none were HPV16 positive, in contrast to HPV16-positive tonsillar carcinomas without disruptive p53 mutations (0% versus 57%; P = 0.008). CONCLUSIONS: Although HPV16 and mutated p53 may coexist in a subset of HNSCCs, HPV16 and disruptive p53 mutations seem to be nonoverlapping events. A less calamitous genetic profile, including the absence of disruptive p53 mutations, may underlie the emerging clinical profile of HPV16-positive HNSCC such as improved patient outcome.     

A subset of head and neck squamous cell carcinomas exhibits integration of HPV 16/18 DNA and overexpression of p16INK4A and p53 in the absence of mutations in p53 exons 5-8

Besides well-known risk factors such as tobacco use and alcohol consumption, oncogenic human papillomavirus (HPV) infection also has recently been suggested to promote head and neck tumorigenesis. HPV is known to cause cancer by inactivation of cell cycle regulators p53 and pRb via expression of viral oncoproteins E6 and E7. This indicates that p53 mutations are not a prerequisite in HPV-induced tumor development. However, discrepancy exists with respect to the frequency of head and neck squamous cell carcinomas (HNSCC) harboring DNA of oncogenic HPV and the fraction of these tumors showing p53 mutations. In our study, we examined the frequency of HNSCC demonstrating HPV 16/18 integration as identified by fluorescence in situ hybridization (FISH) and investigated their p53 (mutation) status by immunohistochemistry and single-strand conformation polymorphism (SSCP) analysis of exons 5-8. Paraffin-embedded, archival biopsy material from 27 premalignant mucosal lesions and 47 cases of HNSCC were analyzed. Ten of the 47 (21%) HNSCC unequivocally exhibited HPV 16 integration, including 8 of 12 (67%) tonsillar carcinomas. This is supported by the immunohistochemical detection of p16(INK4A) overexpression in all 10 HPV-positive tumors. Although FISH is considered to be less sensitive than PCR-based methods for HPV detection, our data clearly demonstrate clonal association of HPV with these tumors, as illustrated by the presence of integrated HPV 16 in both the primary tumor and their metastases in 2 patients. In contrast, HPV 16/18 DNA could not be detected in the premalignant lesions. In 30 of 47 (64%), HNSCC accumulation of p53 was observed, including 8 of the 10 HPV-positive carcinomas. However, in none of the latter cases could mutations in exons 5-8 be identified, except for a polymorphism in codon 213 of exon 6 in one patient. Evaluation of clinical data revealed a significant inverse relation between tobacco use with or without alcohol consumption, and HPV positivity of the tumors.     

The significance of p53 codon 72 polymorphism for the development of cervical adenocarcinomas.

Infection with the human papillomavirus is an important co-factor in the development of cervical carcinomas. Accordingly, HPV DNA is recognised in most of these tumours. Polymorphism of the p53 gene, codon 72, is also considered a risk factor in the development of cervical carcinoma. However, this finding is contradicted by several observers. In the present investigation, 111 cases of adenocarcinoma of the cervix collected through the Swedish Cancer Registry and 188 controls (females with normal cytology at organised gynaecological screening) were analysed with regard to p53, codon 72, polymorphism using a PCR- and SSCP-based technique. In the controls, 9% showed pro/pro, 44% pro/arg and 47% arg/arg, whereas in the invasive adenocarcinomas, the corresponding figures were 0%, 29% and 71%, respectively. The difference was statistically significant (P = 0.001). HPV DNA was identified in 86 tumours (HPV 18 in 48, HPV 16 in 31 and HPV of unknown type in 7 cases) and 25 tumours were HPV negative. The p53, codon 72, genotypes observed in HPV-positive and HPV-negative cervical adenocarcinomas were not statistically different (P = 0.690). The results indicate that women homozygotic for arg/arg in codon 72 of the p53 gene are at an increased risk for the development of cervical adenocarcinomas. However, this genetic disposition seems to be unrelated to the HPV infection.     

ras,p53 and hpv status in benign and malignant prostate tumors

To study the role of ras, p53 genes and HPV virus (16 and 18) in the development of prostate cancer, we analyzed tissue sections from 27 patients affected with carcinomas (stages A to D) and from 24 patients with adenomas. Mutations of H, K and N-ras and p53 (exons 2-9) were studied by SSCP and DNA sequencing. Accumulation of p53 protein was studied by immu-nohistochemistry on tissue sections. Tumors were also analyzed for the presence of HPV 16 and -18 sequences by PCR and DNA hybridization with sequence-specific oligonucleotides. No mutation was found in the three ras genes studied, either in carcinomas or adenomas. By SSCP analysis we identified p53 mutations in only 2 of 19 carcinomas studied, both in exon 7. Immunohistochemical results strongly correlate with the SSCP results: p53 protein was positive in tumors with p53 mutation but not in others; 32% of studied adenomas had detectable HPV16 DNA, while 53% of carcinomas were HPV16+. Among these I presented a p53 mutation. No HPV 18 E6 sequence could be detected. Our data show that in prostate tumors from France, mutations of p53 and ras are rare events but that these tumors display detectable HPV 16 DNA at a high frequency. The low incidence of p53 mutation, associated to a significant proportion of tumors showing HPV16 DNA, could suggest that in prostate cancer HPV 16 infection could participate in p53 inactivation by E6. © 1995 Wiley-Liss, Inc.     

High frequency of p53 protein expression in thymic carcinoma but not in thymoma.

Thymic epithelial tumours are broadly classified into thymomas and thymic carcinomas. Although both tumours occasionally show invasive growth, they exhibit different clinical and biological findings. The oncogene and anti-oncogene in thymic epithelial tumours have not been evaluated fully. We investigated the expression of p53 protein by immunohistochemical analysis using the anti-p53 polyclonal antibody (CM-1) in 17 thymomas and 19 thymic carcinomas. We also examined p53 gene (exon 5-8) mutation in 18 thymic carcinomas by using polymerase chain reaction-single-strand conformation polymorphism methods and direct sequencing. Of the thymoma cases, only one invasive thymoma showed focal nuclear staining. Fourteen of the 19 thymic carcinomas (74%) showed nuclear staining. Point mutations of the p53 gene were recognized in only 2 of the 18 thymic carcinomas (11%). One was the mutation C to T transition in the first letter of codon 222 in exon 6, which results in the amino acid substitution from proline to serine. Another was a silent mutation. p53 protein accumulation is highly frequent in thymic carcinomas but not in thymomas, and gene mutation is uncommon in thymic carcinomas.     

Analysis of skin cancer risk factors in immunosuppressed renal transplant patients shows high levels of UV-specific tandem CC to TT mutations of the p53 gene

Immunosuppressed renal transplant recipients (RTRs) are predisposed to non-melanoma skin cancers (NMSCs), predominantly squamous cell carcinomas (SCCs). We have analyzed skin lesions from RTRs with aggressive tumors for p53 gene modifications, the presence of Human Papillomas Virus (HPV) DNA in relation to the p53 codon 72 genotype and polymorphisms of the XPD repair gene. We detected 24 p53 mutations in 15/25 (60%) NMSCs, 1 deletion and 23 base substitutions, the majority (78%) being UV-specific C to T transitions at bipyrimidine sites. Importantly, 35% (6/17) are tandem mutations, including 4 UV signature CC to TT transitions possibly linked to modulated DNA repair caused by the immunosuppressive drug cyclosporin A (CsA). We found 8 p53 mutations in 7/17 (41%) precancerous actinic keratosis (AK), suggesting that p53 mutations are early events in RTR skin carcinogenesis. Immunohistochemical analysis shows a good correlation between p53 accumulation and mutations. HPV DNA was detected in 78% of skin lesions (60% Basal Cell Carcinomas, 82%AK and 79% SCCs). Thus, immunosuppression has increased the risk of infections by HPVs, predominantly epidermodysplasia verruciformis, speculated to play a role in skin cancer development. No association is found between HPV status and p53 mutation. Moreover, p53 codon 72 or frequencies of three XPD genotypes of RTRs are comparable with control populations. The p53 mutation spectrum, presenting a high level of CC to TT mutations, shows that the UV component of sunlight is the major risk factor and modulated DNA repair by immunosuppressive drug treatment may be significant in the skin carcinogenesis of RTRs.