Monoclonal antibody against a tumor-associated sialoglycoprotein of superficial papillary bladder tumors and cervical condylomas

Noninvasive Urine-Based Tests to Diagnose or Detect Recurrence of Bladder Cancer

Liquid biopsies are increasingly used for the diagnosis and follow-up of cancer patients. Urine is a body fluid that can be used to detect cancers and others diseases. It is noninvasive and easy to collect. To detect Bladder Cancer (BC), cytology is the first assay used. It is an effective way to detect high grade BC but has a high rate of equivocal results, especially for low grade BC. Furthermore, cystoscopy is used to confirm cytology results and to determine cancer status. Cystoscopy is also effective but highly invasive, and not well accepted by patients, especially for BC follow-up. In this review we survey the numerous assays recently developed in order to diagnose BC at an early stage, and to facilitate the follow-up of patients. We discuss their effectiveness, ease of use, and applications. Finally, we discuss assays that, in the future, could improve the diagnosis and management of BC patients.

Comparative evaluation of ProEx C and ImmunoCyt/uCyt assays in atypical urine cytology

CONTEXT

Detection of urothelial carcinoma by urine cytology can be challenging. Recently, ProEx C has been studied as a marker to improve detection of urothelial carcinoma. ProEx C is an assay targeting expression of topoisomerase II-α and the minichromosome maintenance protein-2 and is used to assist in diagnoses of gynecologic specimens.

OBJECTIVE

To evaluate the utility of ProEx C and uCyt in atypical urine cytology.

DESIGN

Sixty-eight specimens with a diagnosis of atypical urine cytology, concurrent uCyt testing, and surgical biopsy follow-up were included. Slides were restained with ProEx C. ProEx C was recorded as positive when nuclear staining was seen in at least one morphologically atypical urothelial cell. The uCyt was scored as positive if at least one morphologically atypical urothelial cell showed positive fluorescence staining. Thirteen cases (19%) had benign histologic diagnoses, 18 (26%) had low-grade papillary urothelial carcinoma, and 37 (54%) had high-grade urothelial carcinoma.

RESULTS

The overall sensitivity was 85% for ProEx C, 85% for uCyt, and 93% for the combination of the 2 assays. The overall specificity was 69% for ProEx C, 31% for uCyt, and 23% for the combination of the 2 tests. In predicting high-grade urothelial carcinoma, sensitivity was 92% for ProEx C, 86% for uCyt, and 92% for both tests. In predicting low-grade papillary urothelial carcinoma, sensitivity was best with the combination of the 2 tests at 94%.

CONCLUSION

ProEx C has superior specificity to uCyt. The combination of the 2 tests yielded high sensitivity not only for high-grade urothelial carcinoma but also for low-grade papillary urothelial carcinoma.

Urothelial carcinoma with abundant myxoid stroma

Urothelial carcinomas with abundant myxoid stroma have thus far been only briefly reported in a couple of textbooks yet not in the peer-reviewed literature. Thirteen cases of urothelial carcinoma with myxoid features were collected over 9 years. Cases with any distinct adenocarcinoma component were excluded from the study. The mean age of the patients was 64 years (range, 45-84 years). Nine of the 13 were male. All cases involved the bladder with one of the cases involving a bladder diverticulum. Treatment included transurethral resection of the bladder only in 6 patients, transurethral resection of the bladder with subsequent intravesical bacillus Calmette-Guérin treatment in 4 patients, radical cystectomy only in 2 patients, and neoadjuvant chemotherapy followed by cystectomy in 1 patient. In all cases, the myxoid stroma was associated with invasive urothelial carcinoma. The 2 most common patterns of cancer with myxoid stroma were small- or medium-sized nests seen in 10 cases followed by filiform cancer seen in 4 cases. Other patterns of invasive cancer associated with myxoid stroma were short cords and individual cells. The percentage of invasive urothelial carcinoma that had myxoid stroma ranged from 5% to 95% (mean, 50%). An unusual finding was the presence of invasive low-grade urothelial carcinoma associated with myxoid stroma in 5 cases, 4 of which had an overlying low-grade papillary urothelial carcinoma component. All cases were uniformly positive for cytokeratin 7 and negative for CDX2 with 5 cases also positive for cytokeratin 20. Urothelial carcinoma associated with the extracellular myxoid matrix was positive for MUC5 in 3 cases and for MUC2 in 2 cases. Two of the MUC5-positive cases were also positive in the urothelium for polyclonal CEA. Histochemical stains for Alcian blue with and without hyaluronidase, periodic acid-Schiff, and mucicarmine showed positivity in the areas of myxoid differentiation. The current study describes a rare variant of urothelial carcinoma that may be confused with primary or secondary adenocarcinoma of the bladder, which can have therapeutic and prognostic implications.

[Tumor marker tests in bladder cancer]

The gold standard for detecting bladder cancer is cystoscopy which identifies nearly all papillary and sessile lesions. However, it is an invasive procedure causing some discomfort for patients. Urine cytology is the standard non-invasive marker with very high specificity, but unfavourable poor sensitivity for Ta, G1, and T1 bladder tumors. To improve early detection of bladder cancer as well as to monitor treatment response and tumor recurrence, bladder tumor markers are eligible. An ideal bladder cancer test would have the potential to replace or delay cystoscopy in the follow-up of bladder cancer patients. In recent years, the FDA approved non-invasive tumor marker tests ImmunoCyt / uCyt+, BTA TRAK, BTA stat, NMP22, NMP22 BladderChek, and UroVysion have been investigated. The tests demonstrated higher sensitivity for diagnosis of bladder cancer compared to urine cytology. Overall, the mean sensitivity and mean specificity was 64-80% and 71-95% and the mean positive and negative predictive values to detect malignancy were 49-84% and 79-95%, respectively. BTA TRAK, BTA stat, NMP22, and NMP22 BladderChek assays are limited by false-positive results in patients with benign urological diseases such as hematuria, urocystitis, renal calculi or urinary tract infections. Due to low specificity BTA TRAK, BTA stat, NMP22, and NMP22 BladderChek should not be used without first ruling out benign or malignant genitourinary disease other than bladder cancer. With the exception of UroVysion achieving 80% sensitivity and 94% specificity, none of these non-invasive tests revealed a high sensitivity and specificity at the same time, which is a main demand to be made on an ideal tumor marker. Insufficient sensitivity along with limited specificity does not allow replacing cystoscopy in diagnosis of bladder cancer or treatment decisions based on a positive test result.

Urinary markers of bladder carcinoma

PURPOSE

Transitional cell carcinoma of bladder is one of the most common tumors of genitourinary tract. Cystoscopy along with cytology is the mainstay for diagnosing bladder cancer. Cytology is specific for diagnosis of bladder carcinomas but less sensitive particularly in low-grade disease. Cystoscopy on the other hand is invasive and relatively costly technique and may also be inconclusive at times particularly in case of cystitis. A simple noninvasive marker for detecting bladder cancer would be helpful. A clinically useful urinary marker should be easy to perform, should have minimum requirements for sample preparations and should have high sensitivity and specificity in diagnosis. In this review we discussed the various urinary markers and their role in detection of bladder cancer.

MATERIALS AND METHODS

We reviewed the literature on urinary markers and tests that may have clinical usefulness.

RESULTS

Several urinary markers and tests such as BTA Stat, BTA TRAK, NMP22, telomerase, HA and HAse tests, Immunocyt, Quanticyt, FDP, BLCA-4, FISH, CYFRA-21-1 have enough potential for future clinical use. BTA stat, NMP22 (bladder check)and AccuDX (FDP) tests are presently point of care tests. The rest of the tests are laboratory-based and may need trained technicians. Majorities of the urinary markers have higher sensitivity and specificity than cytology. However, voided urinary cytology has the highest specificity.

CONCLUSIONS

Till now there is no urinary marker or test that can replace the need of cystoscopy. However, some markers have the potential for future clinical use.

Identification of two genes differentially expressed upon different spatial configuration of the MGH-U3 human bladder cancer cells

By using mRNA differential display technology, we have compared gene expression in neoconfluent (actively proliferating) and 14-day confluent (non-proliferative) MGH-U3 cells. Two clones (6.17.6 and 10.9.2) displayed significantly increased expression in the 14-day confluent MGH-U3 cells, as confirmed by Northern blot analysis. Nucleotide sequence showed that clone 6.17.6 was part of the human insulin-like growth factor binding protein-5 (IGFBP-5) cDNA, while clone 10.9.2 was part of a human gene with unknown function (clone HSI12602). The differential IGFBP-5 expression in this model system was also evidenced by Western analysis. The possible anti-proliferative role of IGFBP-5 in this model system is briefly discussed.

Detection of upper urinary tract transitional cell carcinoma with ImmunoCyt: a preliminary report

OBJECTIVES

To assess the clinical performance of ImmunoCyt in the detection of upper urinary tract transitional cell carcinoma (UT-TCC). This newly developed immunocytochemical test detects three cellular markers specific for TCC.

METHODS

Thirty-seven patients with symptoms and/or findings on imaging suggestive of UT tumors were prospectively evaluated. All patients underwent a standard cytologic evaluation and ImmunoCyt testing of voided urine, as well as imaging studies. Urine samples were also obtained from the UT of 32 patients by ureteral catheterization and tested by cytologic analysis and ImmunoCyt.

RESULTS

Sixteen patients had UT-TCC as documented by the final histologic evaluation. The sensitivity of testing the voided urine from 37 patients was 50% for cytologic analysis, 75% for ImmunoCyt, and 87% for both methods combined. The cytologic evaluation detected no G1, 1 (17%) of 6 G2, and 7 (100%) of 7 G3 tumors. ImmunoCyt detected 1 (33%) of 3 G1, 6 (100%) of 6 G2, and 5 (71%) of 7 G3 tumors. The sensitivity in the 32 urine samples obtained from the UT was 82% for cytologic analysis, 91% for ImmunoCyt, and 100% for both methods combined. Cytologic analysis detected all G2 and G3 (100% sensitivity) and no G1 tumors. ImmunoCyt detected 2 (100% sensitivity) of 2 G1, 4 (100%) of 4 G2, and 4 (80%) of 5 G3 tumors. The test specificity, calculated in 21 patients free of TCC, was 100% for cytologic analysis in voided and ureteral urine specimens and 95% and 100% for ImmunoCyt in voided and ureteral urine samples, respectively.

CONCLUSIONS

The results of this preliminary study show that ImmunoCyt complements cytologic analysis in detecting UT-TCC, mainly because of its high sensitivity to low-grade TCC. The combination of cytologic testing and ImmunoCyt gives 100% sensitivity in detecting UT-TCC in UT urine samples.

Monoclonal antibodies : generation and clinical use

Originally, the term "antibody" referred to an unknown entity in serum, which had the capacity to neutralize pathogenic bacteria. Ehrlich discovered that the socalled antibody had to be a discrete substance, and was the first to propose a theory on antibody formation (1). A few years later, he hypothesized that antibodies might be applied for selective treatment of cancer, provided that the antibody showed specificity for the tumor tissue (2 ). Later studies showed that antibodies could be produced against a wide variety of substances, including tumors.

Immunocyt: a new tool for detecting transitional cell cancer of the urinary tract

PURPOSE

The limitations of cytology and the invasiveness of cystoscopy for detecting bladder cancer generate increasing interest in noninvasive, urine bound diagnostic tools. We assessed the diagnostic value of the newly developed immunocytochemical test, Immunocyt, which detects cellular markers specific for transitional cell cancer in the voided urine of patients with bladder cancer.

MATERIALS AND METHODS

Participating in our prospective study were 264 consecutive patients with a mean age of 65.9 years, including 114 in whom symptoms were suggestive of bladder cancer and 150 who were being followed after complete transurethral resection of superficial transitional cell carcinoma. Voided urine specimens were evaluated by standard cytology and the Immunocyt test, which traces the monoclonal antibodies M344, LDQ10 and 19A211 against transitional cell carcinoma in exfoliated urothelial cells. In all cases cystoscopy was subsequently performed and any suspicious lesion was evaluated by biopsy.

RESULTS

Histologically proved transitional cell carcinoma was found in 79 patients. Immunocyt with cytology had 89.9% sensitivity overall (84, 88 and 96.5% in grades 1 to 3 disease, respectively). A total of 34 (43%), 3 (3.8%) and 34 (43%) cases were positive on Immunocyt only, cytology only and both evaluations, respectively. In 8 cases (10.1%) both tests were negative. Overall Immunocyt only was 86.1% sensitive (84, 84 and 89.6% in grades 1 to 3 disease, respectively) and 79.4% specific. Overall cytology only was 46.8% sensitive (4, 52 and 79.3% in grades 1 to 3 disease, respectively) and 98.2% specific.

CONCLUSIONS

Immunocyt is a noninvasive, highly sensitive test for detecting transitional cell carcinoma of all grades and stages. When combined with conventional urinary cytology, it may replace cystoscopy in select patients, especially in followup protocols of low grade transitional cell carcinoma.

Influence of spatial configuration on the expression of carcinoembryonic antigen and mucin antigens in human bladder cancer

CEA and cellular mucin antigens have been recognized as potential targets for specific immunotherapy and are frequently expressed in bladder cancer. We studied the coordinated expression of a bladder cancer-associated CEA glycoform and of the mucins MUC1, MUC2 and MAUB under various growth conditions in the MGH-U3 bladder-cancer cell line. CEA and MUC2 mRNAs and proteins were detected in nude mouse tumors and spheroids but not in monolayer cultures. Expression of MAUB and bladder-cancer CEA also was induced according to spatial configuration of cells. MUC1 was always expressed under various growth conditions, but its glycosylation was modulated: in spheroids and mostly in tumor cells, the SM3 protein epitope was unmasked and sialyl-Tn was induced. The kinetics of modulation of MAUB and bladder-cancer CEA were different. The epitope recognized by the monoclonal antibody (MAb) 19A211 was rapidly induced in the aggregation phase of spheroid formation and rapidly lost upon plating of tumor cells, suggesting a relationship with cell contact. By contrast, MAUB induction in spheroids was delayed to the compaction phase, when cell aggregates become resistant to disruption, and loss of expression upon tumor plating occurred slowly over several culture passages. No induction of these 2 antigens was observed in the presence of differentiation agents, endothelial cell products or interferon-gamma, but it occurred when MGH-U3 cells were cultured at high density on extracellular matrix. Our results suggest that CEA and mucin antigen expression in bladder cancer is modulated by the spatial configuration of cells.

Biochemical analysis of a bladder-cancer-associated mucin: structural features and epitope characterization

Three monoclonal antibodies (mAbs), M344, M300 and M75, were shown to define a unique tumour-associated antigen (TAA) of superficial bladder tumours. The antigenic determinants are expressed on a very-high-molecular-mass component and, in about 50% of the positive samples, one determinant is also detected on a 62 kDa molecular species, observed only under reducing conditions. The objectives of the present study were to characterize further this TAA by analysing (1) the biochemical nature of the epitopes recognized by the three mAbs, and (2) the biochemical and structural features of the molecule bearing them. The antigenicity was resistant to heat denaturation, trypsin and alpha-chymotrypsin treatments but highly sensitive to papain and Pronase digestion. NaIO4 oxidation decreased reactivity to mAbs M344 and M300 but enhanced reactivity to mAb M75. The three determinants were insensitive to beta-galactosidase and alpha-L-fucosidase but were sensitive to Vibrio cholerae neuraminidase. None of the three mAbs reacted with ovine, bovine or porcine submaxillary mucins. Deglycosylation with O-glycosidase or trifluoromethanesulphonic acid completely abolished the reactivity of the mAbs whereas N-glycosidase F deglycosylation had no appreciable effect. The presence on the molecule of cryptic Gal(beta(1-3))GalNAc as a major core disaccharide was demonstrated by a heterologous sandwich assay using mAb M75 and peanut agglutinin. Thiol reduction using beta-mercaptoethanol increased mobility of the high-molecular-mass component in polyacrylamide gels. We thus conclude that mAbs M344 and M300 react with sialylated carbohydrate epitopes, and mAb M75 reacts with a partially cryptic and periodate-resistant sialylated epitope expressed on a typical secreted high-molecular-mass oligomeric mucin which we named MAUB for mucin antigen of the urinary bladder.

MAUB is a new mucin antigen associated with bladder cancer

The M344 tumor-associated antigen, expressed in 70% of superficial bladder tumors, is a sialylated carbohydrate present on a high molecular mass thiol-reducible secreted mucin, which we named MAUB for mucin antigen of the urinary bladder. Herein we studied the relationship between MAUB and other known mucins in the MGH-U3 bladder cancer line where MAUB expression is modulated by culture conditions. Northern blots, immunoradiometric assays, and Western blots showed that only MUC1 and MUC2 are expressed in this MAUB-positive cell line. MUC1 differs from MAUB by its molecular mass and its non-oligomeric nature, while MUC2 has similar molecular mass and response to culture conditions. However, in double determinant immunoradiometric assays, MAUB and MUC2 did not cross-react. Moreover, confocal microscopy showed different subcellular localization of the two antigens. Treatment of MGH-U3 cells with MUC2 antisense oligodeoxynucleotides resulted in decreased expression of MUC2 and increased expression of MAUB, ruling out the possibility that monoclonal antibody M344 recognizes a different glycosylated form of MUC2. In addition, we identified a tumor specimen expressing MAUB but no MUC2 antigen or mRNA. Together, these results suggest that there is expression of at least three mucins in MGH-U3 cells and that MAUB is a cancer-associated mucin distinct from those identified so far.

Rat liver cytochrome P450 2B3: structure of the CYP2B3 gene and immunological identification of a constitutive P450 2B3-like protein in rat liver

The cytochrome P450 2B subfamily in the rat contains an estimated eight to eleven members at the genomic level. Synthesis in the liver of the prototypic forms P450 2B1 and P450 2B2 is dramatically induced by phenobarbital. The 1.9-kb mRNA for P450 2B3, a third member of the P450 2B subfamily, is constitutively present in rat liver but is not inducible by phenobarbital. We have now cloned and sequenced exonic sequences corresponding to the entire 2B3 mRNA and determined their exon-intron structure, which is identical to that of CYP2B1/CYP2B2 and other CYP2B genes. A putative CYP2B3 transcription start site was identified and CYP2B3 5'- and 3'-flanking sequences were compared to those of CYP2B1 and CYP2B2. CYP2B3, like CYP2B1 and CYP2B2, has a modified TATA box preceding the transcription start site and lacks the canonical polyadenylation signal preceding the poly(A) site. A 2B3 expression vector, pMT2-2B3, directed the synthesis in COS-1 cells of an approximately 50-kD protein detectable on Western blots with a polyclonal antibody and with one of four monoclonal antibodies raised against 2B1 but not with a polyclonal antibody raised against P450 PB6. The 2B3 protein migrated with a slightly higher electrophoretic mobility than 2B1 and comigrated with a protein detected by anti-2B1 antibodies in liver microsomes from untreated rats. The results indicate that a 2B3-like protein is present in rat liver and that it is distinct from P450 PB6 and other known constitutive rat hepatic P450s.

Enhanced expression of a tumor-cell-derived collagenase-stimulatory factor in urothelial carcinoma: its usefulness as a tumor marker for bladder cancers

A mouse monoclonal antibody (MAb) E11F4, previously raised against the tumor-cell-derived collagenase-stimulatory factor (TCSF) from LX-1 human lung-carcinoma cells, has been used to define the expression and distribution of TCSF in human non-neoplastic urothelium and tumors of the urinary bladder. Immunohistochemically, TCSF was detected in 27/28 transitional-cell carcinomas (TCC) of the bladder, of which 23 were judged to be positive for TCSF according to objective criteria. Twenty-four of 28 non-neoplastic urothelium from 22 individuals were judged to be negative for TCSF by this criteria. However, TCSF immunostaining that was confined to the superficial umbrella cells was frequently observed in non-neoplastic urothelium. In bladder carcinomas, TCSF was in most cases demonstrated in the majority of cells, including at the invasion front. Its localization to the cell membrane was demonstrated by immunoelectron microscopy. The high level of expression of TCSF in bladder tumors, but not in non-neoplastic urothelium, was also demonstrated by immunoblotting of tissue extracts. Furthermore, E11F4 immunostaining identified tumor cells obtained from bladder washings or voided urine and detected more TCC cases than conventional cytology. Since TCSF immunostaining was positive even in low-grade TCC (immunohistochemically and immunocytochemically in 4/5 TCC grade I), the application of TCSF immunostaining to urine cytology appears promising as a valuable adjunct to conventional methods in the clinical evaluation of patients with TCC.

Blood group antigens in normal and neoplastic urothelium

The ABO and Lewis blood group antigens are cell surface carbohydrate determinants formed by the sequential addition of saccharides to precursor backbone structures of membrane lipids and proteins. Suppression of normally active glycosyltransferases results in the absence of antigens that are normally expressed. ABH antigen deletion in malignant and premalignant urothelium has been extensively evaluated; it appears to correlate with significantly higher rates of tumor recurrence and disease progression. However, we have recently shown that the ABH blood group system is differentially expressed in the normal urothelium of secretors in contrast to nonsecretor individuals. The normal urothelium of nonsecretors does not express A, B or H determinants; therefore, deletion of ABH antigens can only be ascertained in secretor individuals. Although nonsecretors only comprise 22-24% of the population, this observation mandates a reevaluation of earlier studies. Deletion of A, B or H antigens is noted in carcinoma in situ (CIS), and in invasive and metastatic transitional cell carcinoma (TCC) of secretor individuals. Increased synthesis or activation of normally quiescent glycosyltransferases in bladder tumors can result in the expression of aberrant tumor-associated blood group antigens. Immunohistochemical analysis has demonstrated that Lewis X (Le(x)) is not detected in normal adult urothelium except for occasional umbrella cells. However, papillomas, CIS and TCC expressed Le(x) in 84% of cases, regardless of grade, stage, blood type or secretor status of the individual. The presence of Le(x)-positive cells in bladder lavage specimens enhanced the detection of urothelial tumor cells, correctly identifying bladder tumors in 253/293 (86%) cases compared to a 63% sensitivity for cytology alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in antigen expression in superficial bladder cancer

Bladder cancer can be viewed as a prototype for carcinogen-induced neoplasia. This has been demonstrated experimentally in a variety of systems and in man through epidemiological studies of occupational exposure to putative carcinogens. The natural history of this neoplasm demonstrates recurrence in time and space, i.e., multifocal disease. This clinical scenario is precisely what would be expected if a target tissue, e.g., urothelium, was continuously exposed to a weak carcinogen. The detection of gross disease is clinically easy. However, the ability to intervene at early stages and monitor the success of this treatment requires the definition of early markers for bladder cancer. Integrins are a family of cell surface proteins, many of which function as receptors for extracellular matrix components. Normal epithelial cells express the integrin alpha 6 beta 4 in association with an anchoring structure known as the hemidesmosome. Urothelium expresses alpha 6 beta 4 on the basal layer of cells similar to the distribution seen on other epithelial surfaces. Even early stages of bladder cancer demonstrate an alteration in the expression of this integrin. Low-stage bladder tumors express alpha 6 beta 4 diffusely throughout the tumor as well as at the invading margin. Altered expression of alpha 6 beta 4 may be an early marker for bladder cancer which may contribute to an invasive phenotype. A second potential marker is detected by DD23, an IgG1 murine monoclonal antibody triggered by the immunization of a BALB/c mouse with a fresh human bladder tumor specimen. The antigen detected by DD23 is not present on normal urothelial specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Strategies of chemoprevention based on antigenic and molecular markers of early and premalignant lesions of the bladder

Using monoclonal antibodies, we have identified a series of tumor-associated antigens selectively expressed on tumor subtypes with distinct clinical behaviours. The mucinous antigen M344 and the gp200 surface antigen 19A211 are preferentially expressed on papillary superficial tumors and carcinoma in situ lesions of the bladder. The combination of these two antigenic markers in immunocytology and flow cytometry studies of exfoliated cells has improved the sensitivity of detection for bladder tumors. Moreover, the detection of M344- and 19A211-positive exfoliated cells from previously treated but currently tumor-free patients appears to be predictive of tumor recurrence on follow-up. These results, as well as results of bladder mapping studies in tumor patients, suggest that these antigenic changes occur in a premalignant stage and may provide tools to monitor the efficacy of chemopreventive measures. Other markers, such as the surface antigen T138 and the soluble molecules autocrine motility factor (AMF) and tumor collagenase stimulating factor (TCSF), are produced by primary or recurrent tumors with a higher metastatic potential. They may be useful in identifying high risk patients for distant failure. The highly restricted antigen 19A211 is also expressed on cervix condylomas and carcinoma. This observation led us to investigate a possible viral etiology of some bladder cancers. Using PCR techniques, we detected the presence of human papillomavirus (HPV) 16 DNA sequences in a significant proportion of bladder tumors. HPV positivity was inversely correlated with the presence of p53 mutations in exons 5-9 of the same tumors as measured by PCR-SSCP technique. This combination of markers may provide a basis for chemoprevention strategies targeted to distinct etiological events.