Ron tyrosine kinase receptor synergises with EGFR to confer adverse features in head and neck squamous cell carcinoma.

BACKGROUND: Although EGFR inhibitors have shown some success in the treatment of head and neck squamous cell carcinomas (HNSCCs), the results are not dramatic. Additional molecular targets are urgently needed. We previously showed that the loss of Ron receptor activity significantly slowed squamous tumour growth and progression in a murine model. Based on these data, we hypothesised that Ron expression confers an aggressive phenotype in HNSCCs. We prospectively collected and evaluated 154 snap-frozen, primary HNSCCs for Ron and EGFR expression/phosphorylation. Biomarker correlation with clinical, pathological and outcome data was performed. The biological responses of HNSCC cell lines to Ron knockdown, its activation and the biochemical interaction between Ron and EGFR were examined. RESULTS: We discovered that 64.3% (99 out of 154) HNSCCs expressed Ron. The carcinomas expressed exclusively mature functional Ron, whereas the adjacent nonmalignant epithelium expressed predominantly nonfunctional Ron precursor. There was no significant association between Ron and sex, tumour differentiation, perineural/vascular invasion or staging. However, patients with Ron+HNSCC were significantly older and more likely to have oropharyngeal tumours. Ron+HNSCC also had significantly higher EGFR expression and correlated strongly with phosphorylated EGFR (pEGFR). Newly diagnosed HNSCC with either Ron/pEGFR or both had lower disease-free survival than those without Ron and pEGFR. Knocking down Ron in SCC9 cells significantly blunted their migratory response to not only the Ron ligand, MSP, but also EGF. Stimulation of Ron in SCC9 cells significantly augmented the growth effect of EGF; the synergistic effect of both growth factors in SCC9 cells was dependent on Ron expression. Activated Ron also interacted with and transactivated EGFR. CONCLUSION: Ron synergises with EGFR to confer certain adverse features in HNSCCs.

Is p16(INK4a) protein expression in oral ST lesions a reliable precancerous marker?

This study correlates the expression of p16(INK4a) and p53 with the detection of high risk human papillomavirus (HPV) in three clinical grades of smokeless tobacco keratosis (STK) as compared with patients without a history of smokeless tobacco use. Tissue samples, including squamous cell carcinoma (SCC) were evaluated for the expression of p16(INK4a) and p53 by indirect immunohistochemical methods using commercially obtained antibodies. HPV DNA analysis was performed using consensus sequence polymerase chain reaction (PCR). At least focal p16(INK4a) expression was detected in Grade I, II and III STK, SCC and control samples of alveolar ridge keratoses (ARK). p16(INK4a) expression in STK and in ARK was typically weak but was relatively strong in all SCC. Strong p53 nuclear staining was detected in STK, SCC and ARK. HPV DNA was detected in Grade I, II and III STK, SCC and ARK, but did not correlate with p16(INK4a) expression. p16(INK4a) distribution did not correlate with STK grade and does not appear to be related to the detection of HPV DNA by PCR in either STK or in SCC. There is an apparent relationship between the grade of STK and the presence of HPV. HPV was rarely detected in high-grade lesions.

Monoclonal endothelial cell proliferation is present in primary but not secondary pulmonary hypertension.

The etiology and pathogenesis of the vascular lesions characterizing primary pulmonary hypertension (PPH), an often fatal pulmonary vascular disease, are largely unknown. Plexiform lesions composed of proliferating endothelial cells occur in between 20 and 80% of the cases of this irreversible pulmonary vascular disease. Recently, technology to assess monoclonality has allowed the distinction between cellular proliferation present in neoplasms from that in reactive nonneoplastic tissue. To determine whether the endothelial cell proliferation in plexiform lesions in PPH is monoclonal or polyclonal, we assessed the methylation pattern of the human androgen receptor gene by PCR (HUMARA) in proliferated endothelial cells in plexiform lesions from female PPH patients (n = 4) compared with secondary pulmonary hypertension (PH) patients (n = 4). In PPH, 17 of 22 lesions (77%) were monoclonal. However, in secondary PH, all 19 lesions examined were polyclonal. Smooth muscle cell hyperplasia in pulmonary vessels (n = 11) in PPH and secondary PH was polyclonal in all but one of the examined vessels. The monoclonal expansion of endothelial cells provides the first marker that allows the distinction between primary and secondary PH. Our data of a frequent monoclonal endothelial cell proliferation in PPH suggests that a somatic genetic alteration similar to that present in neoplastic processes may be responsible for the pathogenesis of PPH.

P38 delta MAPK promotes breast cancer progression and lung metastasis by enhancing cell proliferation and cell detachment.

The protein p38 mitogen-activated protein kinase (MAPK) delta isoform (p38δ) is a poorly studied member of the MAPK family. Data analysis from The Cancer Genome Atlas database revealed that p38δ is highly expressed in all types of human breast cancers. Using a human breast cancer tissue array, we confirmed elevation in cancer tissue. The breast cancer mouse model, MMTV-PyMT (PyMT), developed breast tumors with lung metastasis; however, mice deleted in p38δ (PyMT/p38δ-/-) exhibited delayed primary tumor formation and highly reduced lung metastatic burden. At the cellular level, we demonstrate that targeting of p38δ in breast cancer cells, MCF-7 and MDA-MB-231 resulted in a reduced rate of cell proliferation. In addition, cells lacking p38δ also displayed an increased cell-matrix adhesion and reduced cell detachment. This effect on cell adhesion was molecularly supported by the regulation of the focal adhesion kinase by p38δ in the human breast cell lines. These studies define a previously unappreciated role for p38δ in breast cancer development and evolution by regulating tumor growth and altering metastatic properties. This study proposes MAPK p38δ protein as a key factor in breast cancer. Lack of p38δ resulted in reduced primary tumor size and blocked the metastatic potential to the lungs.

INTU is essential for oncogenic Hh signaling through regulating primary cilia formation in basal cell carcinoma.

Inturned (INTU), a cilia and planar polarity effector, performs prominent ciliogenic functions during morphogenesis, such as in the skin. INTU is expressed in adult tissues but its role in tissue maintenance is unknown. Here, we report that the expression of the INTU gene is aberrantly elevated in human basal cell carcinoma (BCC), coinciding with increased primary cilia formation and activated hedgehog (Hh) signaling. Disrupting Intu in an oncogenic mutant Smo (SmoM2)-driven BCC mouse model prevented the formation of BCC through suppressing primary cilia formation and Hh signaling, suggesting that Intu performs a permissive role during BCC formation. INTU is essential for intraflagellar transport A complex assembly during ciliogenesis. To further determine whether Intu is directly involved in the activation of Hh signaling downstream of ciliogenesis, we examined the Hh signaling pathway in mouse embryonic fibroblasts, which readily responds to the Hh pathway activation. Depleting Intu blocked Smo agonist-induced Hh pathway activation, whereas the expression of Gli2ΔN, a constitutively active Gli2, restored Hh pathway activation in Intu-deficient cells, suggesting that INTU functions upstream of Gli2 activation. In contrast, overexpressing Intu did not promote ciliogenesis or Hh signaling. Taken together, data obtained from this study suggest that INTU is indispensable during BCC tumorigenesis and that its aberrant upregulation is likely a prerequisite for primary cilia formation during Hh-dependent tumorigenesis.

Molecular evidence that most but not all carcinosarcomas of the uterus are combination tumors.

The pathogenesis of carcinosarcoma is still a subject of controversy. In the present study, molecular techniques were applied to determine the pathogenesis of uterine carcinosarcomas. The patterns of chromosome X inactivation were analyzed, targeting a portion of exon 1 of the human androgen receptor (HUMARA) in malignant epithelial and mesenchymal components. The presence of p53 and K-ras mutations were also analyzed. H&E-stained sections of paraffin-embedded, formalin-fixed tissues were microdissected to obtain both epithelial and nonepithelial lesions from 25 carcinosarcomas, and DNAs were extracted by proteinase K digestion. Following treatment with methylation-sensitive restriction endonuclease (HhaI or HpaII), PCR amplification was performed using nested primers targeted to the HUMARA locus. Mutations in the p53 gene and K-ras gene were found in eight (32%) and six (24%) tumors, respectively. The patterns of chromosome X inactivation were different between the carcinomatous and sarcomatous components of three carcinosarcomas, indicating that these three tumors represent collision tumors. By contrast, the patterns of chromosome X inactivation, K-ras sequence, and p53 sequence were identical in both carcinomatous and sarcomatous components in 21 carcinosarcomas, indicating that these 21 tumors represent combination tumors. One case produced equivocal results that precluded determination of whether it represented a collision or combination tumor. These observations show that although most carcinosarcomas are combination tumors, some develop as collision tumors. The determination of histogenesis in individual cases of carcinosarcoma using molecular markers may be worthwhile, because the result could help predict the prognosis of individual cases and help guide clinical management.

Telomerase is a highly sensitive and specific molecular marker in fine-needle aspirates of breast lesions.

PURPOSE: Telomerase has been detected in a majority of human malignant tumors, making telomerase activity (TA) one key difference between mortal and immortal cells. In this study, we evaluated in blind-trial fashion the association of TA with cytologic and final clinical/pathologic diagnosis in fine-needle aspirates (FNAs) of breast lesions. MATERIALS AND METHODS: In 172 FNAs, including 80 samples that were cytologically malignant, 18 that were atypical but not diagnostic for malignancy, and 74 that were cytologically benign, TA was determined by a modified nonradioactive telomeric repeat amplification protocol (TRAP) assay. Final diagnosis was made by pathologic examination of follow-up surgical material available for all the cytologically malignant samples, a majority of the cytologically atypical samples, and a portion of the cytologically benign samples. RESULTS: TA was detected in 85 of 172 samples. Comparison of the cytologic and histologic diagnoses with TA showed that 80 of 87 samples from patients with breast cancer were telomerase-positive, resulting in a sensitivity of 92%. TA was found in four of five FNAs from carcinomas that were considered cytologically atypical but not diagnostic for malignancy. Eighty of 85 samples from patients with benign breast lesions were telomerase-negative, revealing a specificity of 94%. The five positive cases in this group were all fibroadenomas with low TA. Among the 18 cases with a cytologic diagnosis of atypia, there was a strong positive relationship between TRAP findings and histologic diagnosis. CONCLUSION: The detection of TA in FNAs of breast lesions is a highly sensitive and specific marker of malignancy and may be used as an adjunct in cases with an equivocal cytologic diagnosis.

Desmoid tumor is a clonal cellular proliferation: PCR amplification of HUMARA for analysis of patterns of X-chromosome inactivation.

Desmoid tumor is a locally aggressive, nonmetastasizing soft tissue tumor. Whether desmoid tumor is a truly neoplastic cellular proliferative process or, alternatively, an unchecked reactive process has been a subject of debate. In order to determine whether desmoid tumor is composed of a clonal cell population as opposed to being a polyclonal reactive process, analysis of patterns of X-chromosome inactivation was performed. Hematoxylin and eosin stained sections of paraffin-embedded, formalin-fixed tissues were microdissected to obtain both lesional and normal control samples, and the genomic DNAs were extracted by proteinase K digestion. Following treatment with methylation sensitive restriction endonuclease (Hha I or Hpa II), the genomic DNAs were amplified by polymerase chain reaction (PCR), using nested primers targeted to a highly polymorphic short tandem repeat (STR) of the human androgen receptor (HUMARA). In eight of 12 cases, PCR amplification of the genomic DNAs was successful, and all eight of the amplified cases were heterozygous in the size of the HUMARA target. The remaining cases could not be studied because of failure to amplify DNA. Following digestion with HhaI or Hpa II, uniform patterns of X-chromosome inactivation were found in all eight desmoid tumors, whereas normal control tissue remained heterozygous. These results confirm a clonal composition of the tumors. The demonstration of clonality in the tumors in all eight informative cases indicates that desmoid tumor is a true neoplastic process, not an unchecked polyclonal reactive process.

Analysis of clonality in archival tissues by polymerase chain reaction amplification of PGK-1.

Clonality of archival formalin-fixed tissue sections was analyzed by polymerase chain reaction amplification of a portion of the X-linked phosphoglycerate kinase (PGK-1) gene. Amplification was successful in 29 of 36 cases of uterine endometrioid adenocarcinoma. Five of these cases, including both tumor and control tissue from the same patients, were heterozygous for the BstXI polymorphic site of the PGK-1-amplified product, permitting analysis of clonality. Pretreatment of the DNA with HpaII blocked amplification of one of the two PGK-1 alleles from four of five cases of tumor, indicating the clonal pattern of X chromosome inactivation in these cases. In contrast, in DNA from paired control tissues HpaII pretreatment had no effect, indicating a random pattern of X chromosome inactivation in normal tissue. One of the cases of endometrioid adenocarcinoma contained a high proportion (45%) of nontumor cells, precluding the determination of clonality. We conclude that polymerase chain reaction amplification can be used for the determination of the pattern of X chromosome inactivation in formalin-fixed tissue sections. Such an approach makes it feasible to include specimens from archival tissue collections in the analysis of clonality.

Expression of survivin in normal, hyperplastic, and neoplastic colonic mucosa.

The regulation of apoptotic cell death may have a profound effect on the pathogenesis and progression of colon cancer. Survivin, a member of the inhibitor of apoptosis gene family, has been detected in fetal tissue and in a variety of human malignancies. In the current study, we investigated survivin expression by an immunohistochemical approach in benign, hyperplastic, premalignant, and malignant lesions of the colon. Survivin was detected in all cases of normal colonic mucosa (20/20), hyperplastic polyps (20/20), adenomatous polyps (20/20), and in both well differentiated and moderately differentiated colonic adenocarcinomas (20/20). In the normal colonic mucosa, survivin expression was mostly restricted to the base of the colonic crypts. All epithelial cells showed uniformly intense staining for survivin in hyperplastic polyps. By contrast, adenomas and adenocarcinomas showed a heterogeneous staining pattern with cell-to-cell, gland-to-gland, and regional variability in the intensity of survivin staining. In contrast to the basal preponderance of staining in normal colonic mucosa, numerous survivin positive cells were present at the luminal surface of hyperplastic polyps, adenomatous polyps, and adenocarcinomas. In conclusion, the expression of survivin is not a specific marker of adenocarcinoma of the colon but does show characteristic and reproducible patterns of expression in non-neoplastic proliferative lesions and in normal colonic mucosa.

Association of human papillomavirus with malignant and premalignant lesions of the uterine endometrium.

The possible association of human papillomavirus (HPV) with endometrial hyperplasia and endometrial adenocarcinoma was investigated. DNA from frozen tissues of 30 endometrioid carcinomas of Japanese patients was tested for HPV DNA by Southern blot hybridization analysis. Screening with HPV type 58 probe under low stringency conditions showed the presence of HPV DNA in two of 30 endometrioid carcinomas. High stringency hybridization identified HPV type 16 in the two positive specimens. The presence of HPV was further analyzed by polymerase chain reaction (PCR)-Southern blot analysis of DNA from archival tissue blocks of the initial 30 endometrioid carcinomas as well as an additional 17 endometrioid carcinomas and 13 atypical hyperplasias of the endometrium from Japan and 38 endometrioid carcinomas from the United States. Polymerase chain reaction amplification using type 16-specific HPV primers for a portion of the E6 open reading frame was positive in six of 47 (13%) endometrioid carcinomas from Japan, including two in which HPV 16 was not detected by Southern blot analysis and two of 38 (5%) endometrioid carcinomas from the United States. Polymerase chain reaction amplification using L1 consensus sequence primers was positive for HPV in two of 13 (15%) endometrial hyperplasias, 13 of 47 (28%) endometrioid carcinomas from Japan, and six of 38 (16%) endometrioid carcinomas from the United States. Slot blot hybridization identified HPV type 16 in seven of the L1 PCR products, including all but one specimen testing positive for HPV type, 16 using E6 type specific primers. In situ hybridization was positive for HPVs 16/18 in glandular epithelial tumor cells in six of the PCR-positive specimens. An additional specimen showed staining for HPVs 16/18 in acellular luminal debris in association with squamous metaplasia of the tumor, but staining was negative in the glandular cells of the tumor. Human papillomavirus was not detected by in situ hybridization in the remaining specimen, which was PCR positive for HPV 16. In situ hybridization was weakly positive for HPVs 31/33/35 in one specimen and was weakly positive for HPVs 6/11 in benign endometrial epithelial cells but not in tumor cells of another specimen that tested positive for HPV by L1 PCR. Two dimensional gel electrophoresis performed on two specimens showed that HPV DNAs were integrated into cellular DNA with no episomal coexistence. These findings suggest that HPV, especially HPV 16, may play an etiologic role in a fraction of endometrioid adenocarcinomas.

Carcinosarcoma of the breast: molecular-biological study for analysis of histogenesis.

The histogenesis of carcinosarcoma of the breast is controversial. In the current case, the demarcation between the carcinomatous and sarcomatous components was distinct in all microscopic fields. Immunohistochemical analysis was negative for epithelial membrane antigen (EMA) and keratin in the sarcomatous component and was negative for desmin in the carcinomatous component, suggesting that this tumor could be derived from the two different stem cells. To determine the histogenesis of this tumor, both carcinomatous and sarcomatous lesions were microdissected from formalin-fixed tissues and DNAs were prepared by proteinase K digestion. PCR amplification of the human androgen receptor (HUMARA) short tandem repeat (STR), after Hpa II digestion of the genomic DNA, indicated that the patterns of X-chromosome inactivation were identical in both components. Moreover, both components contained the identical TGT --> TTT transversion in codon 275 of the p53 gene. These observations strongly support the hypothesis that this tumor is derived from a single totipotent stem cell.

Quantitative telomerase expression in glioblastomas shows regional variation and down-regulation with therapy but no correlation with patient outcome.

Despite the nearly ubiquitous expression of telomerase in almost all types of malignant human tumors, studies have shown widely varying positivity in the highest-grade glioma, the glioblastomas (GBMs), ranging from 26% to 100% of tumors analyzed. We have previously shown significant variability in positive versus negative telomerase expression from region to region within the same GBM. In this study, we hypothesized that application of new quantitative methodology would extend our previous observations and identify whether there is heterogeneity in levels of protein expression even within areas positive for telomerase in high-grade gliomas. Finally, we sought to correlate quantitative telomerase expression with patient outcome and therapeutic response. Quantitative analysis was achieved by polymerase chain-based TRAP assay with phosphorimager analysis and compared with clinical information obtained from 19 patients, most with primary, untreated GBMs. Results showed up to 3-fold variability in telomerase levels across multiple regional samples from the same patient, as well as between patients. In 5 of 6 patients with recurrent tumors who had received intervening radiation therapy or chemotherapy, telomerase was downregulated in the second, post-therapy sample. These data provide in vivo corroboration of recent in vitro experiments showing telomerase downregulation after radiation therapy or chemotherapy treatment of cell lines. Our finding of variability in levels of telomerase expression in GBMs parallels the known heterogeneity of these tumors for histologic features and cell growth-related factors. Statistical analysis showed no relationship between TRAP score and either time to clinical progression or time to death.

Detection of human papillomavirus DNA by in situ hybridization and polymerase chain reaction in human papillomavirus equivocal and dysplastic cervical biopsies.

One hundred twenty-one paraffin-embedded cervical biopsy specimens were tested for the presence of human papillomavirus (HPV) DNA by in situ hybridization and polymerase chain reaction. By in situ hybridization using probes for HPV types 6/11, 16/18, 31/33/35, 42/43/44, 51/52, and 45/56, HPV DNA was found in none of 20 normal/squamous metaplasia biopsy specimens, in one of 76 HPV equivocal biopsy specimens, in seven of 12 condyloma/mild dysplasia biopsy specimens, and in 12 of 13 moderate/severe dysplasia biopsy specimens. Polymerase chain reaction using HPV L1 consensus sequence primers followed by filter hybridization of the amplification products was positive for HPV DNA in two of 20 normal/squamous metaplasia biopsy specimens, in 23 of 76 HPV equivocal biopsy specimens, in eight of 12 condyloma/mild dysplasia biopsy specimens, and in 12 of 13 moderate/severe dysplasia biopsy specimens. Among biopsies that tested positive by polymerase chain reaction but that were negative by in situ hybridization, the most commonly identified HPV was type 16. We conclude that although HPV equivocal biopsy specimens contain HPV DNA more frequently than histologically normal tissue, the majority of biopsy specimens in this category test negative for HPV DNA. The clinical significance of a positive test for HPV, in the absence of unequivocal histologic changes, remains to be determined.

Gaucher's disease. An unusual cause of intrathoracic extramedullary hematopoiesis.

A thoracic paravertebral mass in an asymptomatic woman with type 1 Gaucher's disease proved to be due to extramedullary hematopoiesis. This is, to our knowledge, the first case of intrathoracic extramedullary hematopoiesis reported with Gaucher's disease.

Aggressive conjunctival squamous cell carcinoma in three young Africans.

Polymerase chain reaction was used to test for the presence of human papillomavirus in conjunctival squamous cell carcinomas from three young Africans with aggressive disease. Two of these patients had the acquired immunodeficiency syndrome. Test results for human papillomavirus were negative [corrected] in all three cases.

Alteration of the p53 tumor suppressor gene and activation of c-K-ras-2 protooncogene in endometrial adenocarcinoma from Colorado.

The authors previously reported a significant frequency of activating point mutations in codon 12 and 13 of the K-ras gene in endometrial carcinoma and endometrial atypical hyperplasia from Osaka, Japan. They also showed that alterations of the p53 gene are found frequently in those tumors. This study was designed to reveal possible demographic differences in the prevalence of K-ras and p53 mutations in endometrial carcinoma. Tumor-enriched areas of paraffin-embedded histologic sections obtained through the Colorado Central Cancer Registry were isolated and extracted for DNA. Fragments amplified by polymerase chain reaction (PCR) were screened for transforming mutations in codon 12, 13, or 59-63 of K-ras by direct sequencing. Of 38 endometrial adenocarcinomas that were analyzed, K-ras activation was detected in 4 cases (11%), three in codon 12 (a single case with a GGT-->AGT transition, a single case with a GGT-->GAT transition, and a single case with a GGT-->TGT transversion) and one in codon 13 (a GGC-->GAC mutation). The prevalence of K-ras mutations was significantly lower in endometrial carcinomas from Colorado (4 of 38, 11%) than in those from Osaka, Japan (17 of 57, 31%; P = .02). Mutations in exons 5-8 of p53 were screened by PCR-SSCP analysis, and subsequently confirmed by direct sequencing. Mutations in the p53 gene were detected in 5 of 38 endometrial carcinomas from Colorado (13%), including a single base substitution mutation in 3 cases (60%) and a deletion mutation in 2 cases (40%). Mutations in the p53 gene were significantly more frequently found in G3 cancers (3 of 7, 43%) than G1-G2 cancers combined (2 of 31, 6%; P = .025). Although the prevalence of p53 mutations in endometrial carcinomas from Colorado was not significantly different compared to that from Osaka, Japan (9 of 40, 23%), a G:C-->A:T transition at a CpG site, which was the most common base substitution mutation among Japanese, was not included in any tumors from Colorado. A rare polymorphism in codon 213 (CGA-->CGG) was observed in three cases. These observations may indicate that genetic or environmental factors may significantly influence the pathway of endometrial carcinogenesis.

Differential telomerase expression in human primary intracranial tumors.

The telomeric repeat amplification protocol was used to detect expression of telomerase in primary intracranial tumors. Expression was confined to high-grade variants; 10 of 19 glioblastoma multiforme tumors and 5 of 5 primitive neuroectodermal tumors showed telomerase activity. Two of 8 anaplastic gliomas (1 anaplastic oligodendroglioma and 1 anaplastic oligoastrocytoma) were positive for telomerase. Of 16 meningiomas tested, only the 2 atypical variants were positive for telomerase. Two hemangiopericytomas of the central nervous system also showed expression of telomerase. Twenty-two pituitary adenomas (including 6 invasive variants), 2 low-grade gliomas, 2 ependymomas, and 8 nonneoplastic brain specimens were negative. It was concluded that expression of telomerase is found in most glioblastoma multiforme tumors; primitive neuroectodermal tumors appeared to be more uniformly positive. Expression of telomerase in atypical variants of meningioma and hemangiopericytomas of the central nervous system correlated with the potential for aggressive local growth and metastases. Despite the invasive tendency of some pituitary adenomas, telomerase was not detected in these tumors, which suggests that other pathways account for their aggressive behavior.

Detection of human papillomavirus in anorectal squamous cell carcinoma. Correlation with basaloid pattern of differentiation.

Polymerase chain reaction (PCR) and in situ hybridization were used to test for the presence of human papillomavirus (HPV) DNA in cases of anorectal squamous cell carcinoma. Human papillomavirus was detected by PCR with L1 consensus sequence primers in 22 of 27 cases, including 10 of 11 cases with a prominent basaloid pattern and 12 of 16 cases without basaloid patterns of differentiation. Slot blot hybridization identified HPV type 16 as the most common type, present in 7 of 10 cases of basaloid carcinoma and 10 of 12 cases without basaloid features. In situ hybridization confirmed the presence of HPV in tumor cell nuclei of five cases of basaloid carcinoma and in eight cases of squamous cell carcinoma without basaloid pattern. The authors conclude that the prevalence of HPV in cases of anorectal squamous cell carcinoma is unrelated to the presence or absence of a basaloid pattern of differentiation.

Application of clonal analysis. Differential diagnosis for synchronous primary ovarian and endometrial cancers and metastatic cancer.

Simultaneous involvement of the endometrium and the ovary by carcinoma is a familiar problem in the routine practice of surgical pathology. Such cases may be considered either examples of a single primary carcinoma with metastasis or as synchronous primary neoplasms. The distinction between these two possibilities is made based on clinicopathologic observations, and therefore may not be definitive. In the present study, the authors used molecular techniques to analyze the clonal composition of five cases of concurrent adenocarcinomas of the endometrium and ovary that were clinicopathologically diagnosed as synchronous primary tumors. Patterns of X-chromosome inactivation, mutations in the K-ras gene, mutations or allelic loss of the p53 gene, or human papillomavirus detection were identical in both endometrial and ovarian lesions in three of the cases suggesting that those three cases represented single primary tumors with metastases. In both of the other two cases, the patterns of X-chromosome inactivation clearly demonstrated the presence of independent primary tumors. The application of molecular technology may play an important role for the differential diagnosis between synchronous primary carcinomas and a single carcinoma with metastasis.