Detection of human papillomavirus in small cell carcinomas of the anus and rectum

Small cell carcinomas represent <1% of colorectal/anal carcinomas and have a poor prognosis. Anorectal squamous cell carcinomas are often associated with high-risk human papillomavirus (HPV) infection, similar to squamous and small cell carcinomas of the uterine cervix. In HPV infection, the oncoprotein E7 inactivates the tumor suppressor Rb, leading to p16 upregulation; however, in small cell carcinomas, the Rb pathway is often blocked by other mechanisms; thus, increased p16 may not indicate HPV infection. P16 immunohistochemistry (IHC) may have a limited role in evaluating small cell carcinomas for HPV infection. Formalin-fixed, paraffin-embedded tissue sections of previously diagnosed small cell carcinomas of the anus (n=5) and rectum (n=11) were subjected to IHC for p16, CDX2, and p63, followed by in situ hybridization for high-risk HPV. All (100%) cases of anal and rectal small cell carcinomas were positive for p16, and 100% of anal and 82% of rectal small cell carcinomas were positive for high-risk HPV. The majority of cases showed low or very low HPV copy numbers. In 6 cases, HPV was detected only by using the HPV-16 genotype-specific assay detecting very low copy numbers (1 to 2 viral copies). The majority of tumors expressed p63, which was more pronounced in the anal tumors. CDX2 expression was observed predominantly in rectal tumors. High-risk HPV can be detected using in situ hybridization in the majority of anorectal small cell carcinomas, which are uniformly p16 positive by IHC. HPV-targeted therapy could result in better control of these aggressive neoplasms.     

Expression of p16(INK4A), p53, and Rb proteins are independent from the presence of human papillomavirus genes in oral squamous cell carcinoma.

BACKGROUND: The overexpression of p16(INK4A) and suppression of p53 and Rb proteins are key features of oncogenic transformation by human papillomaviruses (HPV) in anogenital cancers. HPV genomes are often detected in cancers of the oral cavity, but it is unclear whether HPV has a specific oncogenic role there. OBJECTIVES: The objectives of the study were to investigate the expression of p53, Rb, and p16(INK4A) proteins and identify HPV infection and viral integration into the host genome. METHODS: Seventy-nine cases of oral squamous cell carcinoma (OSCC) were studied by immunohistochemistry. Polymerase chain reaction (PCR) was performed to identify HPV DNA from the samples. The results were correlated with clinical data. RESULTS: Thirty-three cases were HPV positive for high-risk HPV (HR-HPV) types, of which 27 harbored HPV16. In 25 of 27 HPV16-positive tumors, the HPV16 genome was fully integrated into the host genome, as evidenced by the lack of PCR-amplifiable E2 gene sequences. Forty-five patients were p53 overexpressing, 20 with HR-HPV-positive and 25 with HR-HPV-negative tumors. p16(INK4A) protein was overexpressed in 4 of 31 HR-HPV-positive and 9of 45 HR-HPV-negative cases. Twenty-six of 32 HR-HPV-positive and 37 of 44 HR-HPV-negative samples exhibited pRb nuclear staining. These differences between HR-HPV-positive and -negative tumors were not statistically significant. No correlation was found between these biological factors and tumor location, stage, differentiation grade, or alcohol or tobacco abuse. CONCLUSIONS: A tumor immunophenotype, similar to HPV-related anogenital cancers, is not present in OSCC and highly oncogenic HPV types are therefore unlikely to be specific or independent risk factors for oral cancer.     

Presence of human papillomavirus DNA and abnormal p53 protein accumulation in lung carcinoma.

BACKGROUND: In some carcinomas inactivation of the tumour suppressor gene product p53, either by point mutation or indirectly by the human papillomavirus (HPV), has been suggested as two alternative routes to malignant transformation. To test this hypothesis in lung tumours, 43 lung carcinomas were analysed by in situ hybridisation and polymerase chain reaction (PCR) for the presence of HPV DNA, and the results were compared with p53 protein immunohistochemical analysis. METHODS: The presence of HPV DNA in lung carcinoma was detected by nucleic acid in situ hybridisation for HPV types 6, 11, 16, 18, 31, and 33 using nonradioactively labelled DNA probes. Polymerase chain reaction (PCR) analysis was performed on all cases showing positive HPV DNA labelling by in situ hybridisation and in an additional 13 negative cases. Abnormal nuclear accumulation of the p53 protein was revealed by immunohistochemistry using the avidin-biotin-peroxidase complex method and a CM-1 polyclonal anti-human p53 antibody and a monoclonal mutation-specific Pab 240 p53 antibody. RESULTS: HPV DNA was found by in situ hybridisation in 13 lung carcinomas (30%). In all these cases subtype-specific HPV DNA could also be detected by PCR. Abnormal p53 protein accumulation was seen in 21 of the 43 carcinomas (49%), of which 18 were HPV negative. Twelve (57%) of the CM-1 positive cases were also positive for the mutation-specific antibody Pab 240. There was an obvious inverse relationship between the presence of papilloma viral DNA and abnormal p53 protein accumulation. CONCLUSIONS: p53 plays an important part in the development of lung carcinomas and, in some cases, HPV may contribute to it by binding and inactivating the p53 protein.     

人乳头瘤病毒DNA相关序列与p53基因突变对大肠癌生物学行为的影响50例报告

目的探讨人乳头瘤病毒（ＨＰＶ）ＤＮＡ相关序列与ｐ５３基因突变及ｐ５３蛋白表达的关系及其对大肠癌生物学行为的影响。方法采用ＰＣＲ方法检测大肠癌及癌旁组织、肝转移灶中ＨＰＶＤＮＡ相关序列。并应用ＰＣＲＳＳＣＰ及免疫组化技术分别检测ｐ５３基因突变及ｐ５３蛋白表达。结果在５０例大肠癌中,检出ＨＰＶ１６、１８ＤＮＡ相关序列２６例（５２０％）,其中ＨＰＶ１６ＤＮＡ４例（８０％）,ＨＰＶ１８ＤＮＡ２２例（４４０％）。ｐ５３基因突变率为５６０％。ｐ５３蛋白表达阳性率为４２０％。ＨＰＶＤＮＡ相关序列与ｐ５３基因突变及ｐ５３蛋白表达呈正比关系。结论ＨＰＶＤＮＡ相关序列可促进细胞转化、致ｐ５３基因突变、抑制细胞的凋亡,与大肠癌的发生发展有密切关系。     

Most basal-like breast carcinomas demonstrate the same Rb-/p16+ immunophenotype as the HPV-related poorly differentiated squamous cell carcinomas which they resemble morphologically

Basal-like carcinomas (BLCs) of the breast share discriminatory morphologic features with poorly differentiated high-risk human papilloma virus (HPV)-related squamous cell carcinomas of the oropharynx, penis, and vulva. Because HPV E7 protein inactivates the retinoblastoma (Rb) protein, diffuse p16 expression is a surrogate marker for these high-risk HPV-related carcinomas. HPV E6 protein also inactivates p53, further compromising the G1-S cell cycle checkpoint. The Rb/p16/p53 immunohistochemical profile of BLC of the breast has not been well characterized. Tissue microarrays containing 71 invasive ductal carcinomas (IDCs) of the breast were immunolabeled for p16, Rb, p53, and Ki-67. The cases included 4 distinct groups of IDCs having surrogate immunohistochemical profiles corresponding to categories defined by gene expression profiling (17 luminal A, 7 luminal B, 14 HER-2+, and 21 BLC), along with 12 unclassifiable triple negative carcinomas (UTNCs). Twenty-five of the 71 IDC were Rb negative/p16 diffuse positive (Rb-/p16+). These included 15 of 21 BLC and 9 of 12 UTNC, but only 1 of 14 HER-2 positive cases and none of the 17 luminal A or 7 luminal B cases (P<0.01, BLC or UTNC vs. others). Six of the Rb-/p16+ IDC also had a significant ductal carcinoma in situ component. The ductal carcinoma in situ in 4 of these 6 cases showed the same Rb-/p16+ phenotype as the associated IDC. BLC and UTNC had the highest Ki-67 indices of the 5 groups, even when matched for grade. The Rb-/p16+ phenotype and the Rb-/p16+/p53 overexpressing phenotype correlated with increased proliferation within the BLC group. In conclusion, BLC and UTNC, but not HER-2, luminal A, or luminal B carcinomas, frequently demonstrate an Rb-/p16+ phenotype, similar to the HPV-related squamous cell carcinomas that BLC resemble morphologically. This subset may represent a more homogenous group than BLC as defined currently.     

Prevalence of human papillomavirus type 16 DNA in squamous cell carcinoma of the palatine tonsil, and not the oral cavity, in young patients: a distinct clinicopathologic and molecular disease entity

Squamous cell carcinoma of the head and neck commonly affects patients in their sixth decade and older, particularly those with a prolonged history of alcohol and tobacco abuse. Less frequently, carcinomas occur in young individuals even in the absence of known risk factors. The purpose of this study is to investigate a possible relationship between these tumors and human papilloma virus (HPV). Thirty-three cases of squamous cell carcinoma of the head and neck in young patients under the age of 40 years were studied: 15 oral, 11 tonsillar, and 7 laryngeal. HPV DNA was detected by polymerase chain reaction in 10 tonsillar and 2 laryngeal carcinomas and in none of the oral tumors. Of the 12 HPV-positive tumors, 11 were HPV16 and 1 was HPV31. HPV-positive tumors had a distinct nonkeratinizing basal cell morphology, they stained diffusely and strongly with p16 antibodies, had higher Ki-67 and lower p53 staining scores as compared with the conventional keratinizing HPV negative carcinomas. It is concluded that in young patients high-risk HPV, particularly HPV16, is strongly associated with tonsillar squamous cell carcinoma and some cases of laryngeal, but not oral, tumors. The HPV-positive carcinomas have a distinct histopathologic and immunophenotypic features.     

Prevalence of high-risk human papillomavirus DNA in nonkeratinizing (cylindrical cell) carcinoma of the sinonasal tract: a distinct clinicopathologic and molecular disease entity

Carcinomas of the nose and paranasal sinuses are a heterogeneous group of neoplasms that differ histologically, biologically, and clinically. Some of these tumors are known to harbor high-risk human papillomavirus (HPV) DNA. In an attempt to identify specific phenotypes associated with HPV infection, 39 cases of sinonasal carcinomas were evaluated by PCR for the presence of HPV DNA. The tumors were also studied with a panel of immunohistochemical stains, including p16, p53, and Ki-67 antibodies. Twenty-one cases were identified as keratinizing squamous cell carcinoma (KSCC) with a male-to-female ratio of 3:1. Eight cases were nonkeratinizing (cylindrical cell) carcinoma (NKCa) with a male-to-female ratio of 1:1. Ten cases were sinonasal undifferentiated carcinoma (SNUC), and 9 of these patients were men. HPV DNA, particularly type 16, was detected in 9 cases: 4 of 21 (19%) of KSCC, 4 of 8 (50%) of NKCa, and 1 of 10 (10%) of SNUC. In addition to a higher prevalence of HPV DNA in NKCa, the tumors also showed a distinct immunophenotype characterized by strong and diffuse staining for p16, high labeling scores for Ki-67, and negative or low reactivity to p53. On the other hand, KSCC and SNUC were either negative or weakly reactive to p16 antibodies. KSCC cases were more likely to be positive and more strongly reactive to p53 stain. Unlike KSCC, SNUC had high Ki-67 labeling scores. These observations suggest that NKCa of the sinonasal tract is a distinct histopathologic and molecular disease entity, which should be added to the list of upper aerodigestive tract tumors with strong etiologic relationship to high risk HPV.     

Distinction of endocervical and endometrial adenocarcinomas: immunohistochemical p16 expression correlated with human papillomavirus (HPV) DNA detection

Determining the origin of uterine adenocarcinomas can be difficult in biopsy and curettage specimens because the morphologic spectrum of endocervical and endometrial adenocarcinomas overlaps. In hysterectomy specimens, the primary site is often equivocal for tumors that involve the lower uterine segment and endocervix and lack identifiable precursor lesions. Most endocervical adenocarcinomas (ECAs) contain high-risk human papillomavirus (HPV) DNA, whereas endometrial adenocarcinomas (EMAs) rarely do. p16 is an inhibitor ofcyclin-dependent kinases, and overexpression of p16 has been observed in cervical intraepithelial lesions and invasive carcinomas associated with high-risk HPV types. We evaluated the utility of immunohistochemistry for p16 in the distinction of ECAs and EMAs. p16 expression was assessed in 24 unequivocal EMAs and 19 unequivocal ECAs and correlated with HPV DNA detection by in situ hybridization and polymerase chain reaction. These assays were then used to assist in the classification of four lower uterine segment/upper endocervical adenocarcinomas (LUS/EC-A) of equivocal origin. p16 expression was moderate-strong and diffuse in 18 ECAs (median 90% of tumor cells positive, range 90%-100%), and weak and diffuse in one. Fourteen of these were positive for HPV DNA, whereas 5 lacked detectable HPV DNA by in situ hybridization; one of these 5 was positive by polymerase chain reaction. In contrast, EMAs displayed weaker staining with patchy distribution (median 30% of tumor cells positive, range 5%-70%) and none contained HPV DNA by in situ hybridization. Two LUS/EC-As, which were positive for HPV, exhibited strong, diffuse p16 expression, consistent with endocervical origin of the tumors. The remaining 2 LUS/EC-As showed patchy p16 staining and did not contain detectable HPV DNA, consistent with the endometrial origin of the tumors. The p16 expression pattern can distinguish ECAs from EMAs. Compared with HPV DNA detection by in situ hybridization, p16 immunohistochemistry appears to be a more sensitive and easier to perform method for distinguishing ECAs from EMAs, can be used to assist in the classification of LUS/EC-As of equivocal origin, and should be evaluated for its utility in the prospective classification of uterine adenocarcinomas in curettage specimens prior to hysterectomy.     

Papillary squamous cell carcinomas of the upper aerodigestive tract: a clinicopathologic and molecular study

BACKGROUND: The limited studies and the small number of published cases of papillary squamous cell carcinoma have precluded accurate assessment of the biologic characteristics of this lesion. METHODS: Thirty-eight of the carcinomas were studied. In-situ hybridization and polymerase chain reaction were performed to detect human papilloma virus (HPV) and p53 expression. RESULTS: HPV was found in 4 of 14 assessable carcinomas by in-situ hybridization and in 5 of 14 by polymerase chain reaction. The most frequently identified HPVs were HPVs in 6/11 and 16/18 patients. In general, a reciprocal relationship was found between p53 and HPV prevalence. The most lethal site for this tumor was the sinonasal tract, whereas patients with papillary squamous cell carcinomas of the larynx had the best outlook. Eleven of 25 (44%) assessable patients died of disease (mean time interval, 2 year). CONCLUSIONS: Papillary squamous cell carcinoma of the upper aerodigestive tract is a distinct variant of squamous cell carcinoma. As such and because of its putative association with HPV, papillary squamous cell carcinoma could be an informative model for defining how viral oncogenes cooperate with other factors in genomic instability, carcinogenesis, and tumor development.     

Human papillomavirus (HPV)-related oropharyngeal nonkeratinizing squamous cell carcinoma: characterization of a distinct phenotype.

We have recently shown that HPV-positive tonsillar carcinoma in young patients exhibits nonkeratinizing basaloid morphology and a characteristic immunophenotype. The purpose of this study was to review a large number of cases of oropharyngeal carcinomas, in all age groups, and to identify tumors with nonkeratinizing morphology. Using polymerase chain reaction (PCR) the prevalence and type of HPV DNA was determined in representative cases and in a control group of conventional keratinizing squamous cell carcinomas. The tumors were further characterized with a panel of immunohistochemical stains. A total of 235 carcinomas were reviewed; 141 of the tonsils and 94 in the base of tongue. Ninety (36%) of the tonsillar and 30 (32%) of the base of tongue carcinomas were nonkeratinizing (NKCa) with basal cell features; the rest were classical keratinizing squamous cell carcinomas (KSCC). HPV DNA, particularly type 16, was identified in 10 (100%) of 10 of NKCA and in only 2 (20%) of 10 of KSCC (P = .0014). NKCas were strongly reactive to p16 antibodies while KSCC showed weak and focal reactivity. Higher Ki67 and lower p53 staining scores were observed in NKCa as compared to KSCC. It is concluded that NKCa of the tonsils and base of tongue is a distinct subtype of squamous cell carcinoma of the head and neck with high prevalence of HPV DNA and a characteristic immunophenotype.     

Expression of p53 protein related to human papillomavirus and DNA ploidy in superficial esophageal carcinoma

We examined the p53 protein and human papilloma virus (HPV) by immunohistochemistry and DNA ploidy by cytofluorometry in paraffin-embedded esophageal carcinoma tissue specimens. Sixty-one patients with superficial esophageal carcinoma were operated on between 1983 and 1991 without any prior treatment. Immunostaining of the anti-p53 protein antibody (CM1) was positive in 32 carcinomas (52%). Patients with p53-positive tumors had a poorer outcome than those with p53-negative tumors (P<0.05). In addition, patients with p53-positive tumors did not have any characteristic site of relapse. Only 5 of the 61 patients (8.2%) had HPV-positive tumors. One of these 5 carcinomas expressed both p53 protein and HPV. Three patients with HPV-positive tumors which had invaded the submucosal layer died of relapse. A determination of DNA ploidy revealed 30 patients with aneuploid tumors, 13 with polyploid tumors and 18 with diploid tumors. The outcome of the patients with aneuploid tumors was worse than that of the patients with diploid tumor (P<0.05). p53 protein expression was not associated with DNA ploidy; however, the 16 patients who had both p53-positive and aneuploid tumors had a worse prognosis than patients with p53-negative and aneuploid tumors (P<0.01). These findings suggest that p53 protein expression in conjunction with DNA ploidy may be a useful indicator in evaluating the prognosis of patients with superficial esophageal carcinoma.     

Immunohistochemical p53 expression patterns in sarcomatoid carcinomas of the upper respiratory tract

Sarcomatoid carcinoma of the upper respiratory tract is a phenotypically complex neoplasm that has triggered much thoughtful discussion regarding histogenic origin and morphologic classification. In particular, its putative epithelial lineage and distinction from a pseudosarcomatous reaction are sometimes questioned. Little is known about the genetic alterations underlying sarcomatoid carcinoma. Although about 45% of conventional squamous cell carcinomas of the upper respiratory tract harbor p53 mutations, the p53 status of sarcomatoid carcinomas is not well established. p53 immunohistochemical analysis using the monoclonal antibody D07 was performed on 23 sarcomatoid carcinomas of the upper respiratory tract. Twenty tumors were biphasic, having dual epithelial and spindled components. In four of these biphasic tumors, the epithelial and spindled components were separately analyzed for p53 gene mutations by sequence analysis. p53 immunohistochemistry was also performed on 19 cases of postradiation stromal atypia. Strong and diffuse p53 staining was detected in 18 (78%) of the 23 sarcomatoid carcinomas. When the spindled component was compared with its corresponding epithelial component, identical patterns of p53 protein expression were noted in 19 (95%) of the 20 biphasic tumors. Weak p53 staining was observed in one (5%) of the 19 cases of postradiation stromal atypia. In the four biphasic tumors evaluated by DNA sequence analysis, p53 status was always the same in the paired epithelial and spindle cell components. These findings help further dispel the notion that sarcomatoid carcinoma represents a reactive spindle cell proliferation (pseudosarcoma) or a collision between a carcinoma and a sarcoma (collision tumor). Instead, the epithelial and spindled components share a common pathway of tumorigenesis despite their conspicuous divergence at the phenotypic level.     

Overexpression of p16INK4 is a reliable marker of human papillomavirus-induced oral high-grade squamous dysplasia.

OBJECTIVE: Human papillomavirus (HPV) infection has been implicated in the development of high-grade squamous dysplasia and carcinoma of the oral cavity in the absence of other known risk factors such as smoking. HPV-induced oral dysplasia or carcinoma may be a unique tumor entity in terms of biologic behavior and treatment decisions. In detecting such cases, most reported studies have used techniques that are less sensitive than DNA amplification. Recent reports have suggested that overexpression of the p16INK4 protein is a surrogate marker of HPV-induced high-grade dysplasia or carcinoma. However, the correlation between expression of p16INK4 and the presence of HPV DNA as determined by polymerase chain reaction (PCR) amplification has not been previously reported. The purpose of this research was to determine if immunohistochemistry for p16 would serve as a marker of HPV-associated high-grade oral squamous dysplasia. STUDY DESIGN: Archival formalin-fixed, paraffin-embedded tissue sections from 41 cases of high-grade oral squamous dysplasia were randomly selected. Expression of p16INK4 protein was assessed by immunohistochemical analysis (16P04 Neomarkers, Fremont, CA). Strong and diffuse nuclear staining restricted to the dysplastic region in the epithelium was scored as positive for protein expression, whereas focal or weak nuclear or cytoplasmic staining was scored as negative. The presence of HPV was determined by microdissection, DNA extraction, and PCR DNA amplification using elongated primers that align with corresponding sequences of the L1 region of 23 mucosotropic HPV genotypes. The HPV type was determined by direct sequencing of the PCR product. Normal squamous epithelium was used as an internal negative control, and cases of severe cervical high-grade squamous dysplasia were used as a positive control for immunohistochemical staining and PCR. RESULTS: The results of immunohistochemical analysis for overexpression of p16INK4 were positive in 6 of the 41 tissue sections. The results of PCR DNA amplification were also positive for these 6 sections. HPV-16 was identified in 5 of the positive cases; in the other case, the viral strain could not be determined. CONCLUSIONS: Immunohistochemical detection of p16INK4 is a technically simple and potentially reliable assay for diagnosing cases of HPV-induced oral high-grade squamous dysplasia. Detecting such lesions may influence future therapeutic decisions.     

p16 overexpression identifies HPV-positive vulvar squamous cell carcinomas

Two types of vulvar squamous cell carcinomas (VSCCs) are recognized according to their relationship to human papillomavirus (HPV). Basaloid or warty carcinomas are considered HPV-associated tumors, whereas differentiated keratinizing neoplasms are considered non-HPV-associated. Recently, immunohistochemical detection of p16 and p53 has been proposed to differentiate these 2 types of VSCCs. We conducted a histologic study with immunohistochemical evaluation of p16 and p53 and HPV detection and typing by polymerase chain reaction using 2 different sets of primers in 92 cases of VSCCs to evaluate the usefulness of immunohistochemistry in the classification of VSCCs and to describe the clinico-pathologic characteristics of both types of VSCCs. HPV was detected in 16/92 (17.4%) specimens, HPV16 being identified in 75% of positive cases. A significant number of discrepancies between histology and HPV detection were observed, with 37.5% of HPV-positive tumors being keratinizing and 9.2% of HPV-negative carcinomas showing basaloid or warty features. Diffuse positivity for p16 and p53 was observed in 100% and 6.2% of HPV-positive tumors and in 2.3% and 64.5% of HPV-negative neoplasms, respectively. The sensitivity and specificity of p16 immunostaining to detect HPV-associated carcinomas (100% and 98.7%, respectively) were better than those of histologic criteria (93.8% and 35.5%) and of p53 negative stain (62.5% and 93.4%). Vulvar intraepithelial neoplasia grade 3 of basaloid/warty type was identified in 53.8% HPV-positive tumors, including 3 keratinizing tumors. All these cases were p16 positive and p53 negative. Vulvar intraepithelial neoplasia grade 3 of differentiated type was observed in 45.6% of HPV-negative cases; 90.8% of them were positive for p53 but all were negative for p16. No differences in age, stage, or development of recurrence were observed between HPV-positive and negative tumors. In summary, the current morphologic criteria to discriminate HPV-positive and negative VSCCs have a significant overlap. Immunostaining for p16 is a reliable marker for HPV-positive VSSCs, which improves the results of histologic classification.     

Overexpression of p27kip1 in urinary bladder urothelial carcinoma

OBJECTIVES: Cyclins and cyclin-dependent kinase (CDK) complexes have important regulatory roles during cell cycle progression and can be used as prognostic markers in various kinds of malignant tumors. This study investigated the expression of proliferative cell nuclear antigen (PCNA), p53, Rb, p27(kip1), and cyclin D1 by immunostains in bladder tumors, especially urothelial papilloma, papillary urothelial neoplasm of low malignant potential, and low and high grade urothelial carcinoma, to see if their expression is associated with classification or grading of the urinary bladder urothelial carcinoma. METHOD: Nuclear expression of PCNA, p53, Rb, p27(kip1), and cyclin D1 was determined immunohistochemically in a series of 89 urinary bladder tumor specimens, including 13 papilloma, 15 urothelial neoplasm of low malignant potential, 17 low grade urothelial carcinoma, and 44 high grade urothelial carcinoma. The results of immunoreactivity were analyzed with respect to the associations with tumor grade. RESULTS: Eighty-two percent (38/45) of the p27(kip1) positive tumors were urothelial carcinoma, and the percentage of the p27(kip1) positivity was higher with increasing grade of the urothelial carcinoma (P = 0.011). A tendency of higher percentage of positive p53 immunoreactivity was noted in the urothelial carcinoma (P = 0.053). There was no significant difference in cyclinD1, Rb and PCNA expression between benign, low malignant potential and urothelial carcinoma. CONCLUSION: We first noted an overexpression of p27(kip1) in urinary bladder urothelial carcinoma. The result indicates that some urothelial carcinomas may tolerate this inhibitor of cell cycle progression.     

Expression of p16 in Sinonasal Undifferentiated Carcinoma (SNUC) Without Associated Human Papillomavirus (HPV)

Sinonasal undifferentiated carcinoma (SNUC) is an uncommon and highly aggressive neoplasm of the paranasal sinuses and nasal cavity. Its undifferentiated histologic appearance often requires immunohistochemical studies to distinguish it from other high-grade neoplasms. Due to the rarity of SNUC, its immunohistochemical staining profile has been incompletely characterized, and little work has been done on its expression of the markers for human papillomavirus (HPV). Our objective is to expand our knowledge of its immunophenotype and its association with HPV in order to define markers with mechanistic potential in the disease process, or of possible therapeutic importance. A total of five patients (one woman and four men) with SNUC, ranging in age from 26 to 75 years (mean 56.8 years) were compared to five patients (five men) with poorly differentiated squamous cell carcinoma (PDSCC), ranging in age from 53 to 75 years (mean 62.2 years). PDSCC was chosen as a control, given its well-reported immunohistochemical profile and negativity for HPV markers. The immunohistochemical panel included: CK7, CK19, EMA, NSE, chromogranin, p53, CK5/6, p63, CK14, S100, HMB-45, desmin, muscle specific actin, and CD45. Additionally, tests for p16, EBV, and HPV (subtypes 6, 11 16, 18) were performed. The diagnosis of SNUC was confirmed in all cases by histology and immunohistochemical stains. An interesting finding of strong diffuse positivity for p16 was noted in all SNUC cases, compared to only two of five PDSCC that were positive for p16. HPV DNA was not detected in any SNUC cases or any cases of PDSCC. All SNUC cases demonstrated over expression of p16 in the absence of HPV DNA expression. This may represent residual epithelial p16 staining, which is normally present in the sinonasal tract. Due to the rarity of SNUC, more cases will need to be evaluated to confirm the absence of HPV DNA.     

Anal cloacogenic and squamous carcinomas. Comparative histologic analysis using in situ hybridization for human papillomavirus DNA

In order to evaluate the morphologic and possible etiologic distinctions between anal cloacogenic and squamous carcinomas, we performed histologic examination and in situ hybridization for human papillomavirus (HPV) DNA on anal canal and anal verge carcinomas from 37 patients. Twenty-one neoplasms were invasive or in situ squamous carcinomas, 14 were invasive cloacogenic carcinomas, and two were unclassified. In situ hybridization was positive for HPV types 16/18 in 12 cases and for types 6/11 in two cases of anal squamous carcinoma (67% HPV positivity overall). All 14 cases classified as anal cloacogenic carcinoma were negative for HPV DNA by this technique. One of the two unclassified carcinomas was positive for type 16/18 DNA. We conclude that anal cloacogenic and squamous carcinomas are histologically similar but distinct neoplasms. Differential expression of HPV DNA in these lesions may be a manifestation of separate mechanisms of pathogenesis, or it may be due to varying degrees of tumor cell differentiation.     

P63 Expression Can Be Used in Differential Diagnosis of Salivary Gland Acinic Cell and Mucoepidermoid Carcinomas

Differentiation of salivary gland acinic cell carcinoma from mucoepidermoid carcinoma can be diagnostically challenging as both may have prominent mucin production. P63 is a p53 homologue required for limb and epidermal morphogenesis. It is expressed in basal and myoepithelial cells of normal salivary gland tissues. In this immunohistochemical study, we examined the expression of p63 in salivary gland acinic cell and mucoepidermoid carcinomas (MEC) and its use in differentiating these two entities. A search was performed and appropriate cases were selected from Lifespan Hospital System archives as well as the consult archives of one author (DRG). 31 salivary gland acinic cell carcinomas (ACC) and 24 MEC were examined for p63 expression by immunohistochemistry. The nuclear immunoreactivity was examined by both authors and was graded semi-quantitatively with negative being less than 10 % of cells staining. Positive staining was graded as follows: 10–25 % of tumor cells staining was weakly positive, 26–75 % of tumor cells staining was moderately positive, and 76–100 % of tumor cells staining was strongly positive. Negative nuclear staining of the tumor cells was seen in 30/31 (96 %) of salivary gland ACC while 1/31 (3 %) showed diffuse nuclear staining of the tumor cells. This latter case was later reclassified as mammary analogue secretory carcinoma following confirmatory molecular testing for the ETV6-NTRK3 fusion gene. Strong positive nuclear staining of the tumor cells was seen in 24 (100 %) of salivary gland MEC cases. P63 is an immunohistochemical stain that can potentially aid in differentiating unusual ACC with prominent mucin production from MEC of the salivary gland. According to this study, acinic cell carcinoma is always negative for p63 immunoreactivity while mucoepidermoid carcinoma is always positive.