William F. Benedict

p53, p21, pRB, and p16 Expression Predict Clinical Outcome in Cystectomy With Bladder Cancer

PURPOSE To determine whether p53, p21, pRB, and/or p16 expression is associated with bladder cancer stage, progression, and prognosis. PATIENTS AND METHODS Immunohistochemical staining for p53, p21, pRB, and p16 was carried out on serial sections from archival specimens of 80 patients who underwent bilateral pelvic lymphadenectomy and radical cystectomy for bladder cancer (median follow-up, 101 months). RESULTS p53, p21, and pRB or p16 expression was altered in 45 (56%), 39 (49%), and 43 (54%) tumors, respectively. Sixty-six patients (83%) had at least one marker altered, and 21 patients (26%) had all three altered. Abnormal expressions of p53, p21, and pRB/p16 expression were associated with muscle-invasive disease (P=.007, P=.003, and P=.003, respectively). The alteration of each marker was independently associated with disease progression (P< or =.038) and disease-specific survival (P< or =.039). In multivariable models that included standard pathologic features and p53 with p21 or p53 with pRB/p16, only p53 and lymph node metastases were associated with bladder cancer progression (P< or =.026) and death (P< or =.028). In models that included p21 and pRB/p16, only p21 and lymph node metastases were associated with bladder cancer progression (P< or =.022) and death (P< or =.028). In a model that included the combined variables p53/p21 and pRB/p16, only p53/p21 and lymph node status were associated with bladder cancer progression (P< or =.047) and death (P< or =.036). The incremental number of altered markers was independently associated with an increased risk of bladder cancer progression (P=.005) and mortality (P=.007). CONCLUSION Although altered expression of each of the four cell cycle regulators is associated with bladder cancer outcome in patients undergoing radical cystectomy, p53 is the strongest predictor, followed by p21, suggesting a more pivotal role of the p53/p21 pathway in bladder cancer progression.

Loss of The Retinoblastoma Tumor-Suppressor Gene in Parathyroid Carcinoma

BACKGROUND The origin and molecular pathogenesis of parathyroid carcinoma are unknown. This life-threatening cause of primary hyperparathyroidism cannot be reliably distinguished from its benign counterpart on the basis of histopathological features alone. Because the PRAD1, or cyclin D1, gene, a cell-cycle regulator, has been implicated in a subgroup of benign parathyroid tumors, we examined the possibility that another cell-cycle regulator with possible functional links to PRAD1, the retinoblastoma tumor-suppressor gene (RB), might be involved in the molecular pathogenesis of parathyroid carcinoma. METHODS Parathyroid carcinomas from 9 patients and adenomas from 21 were studied for evidence of tumor-specific loss of RB gene DNA (allelic loss) by analysis of four DNA polymorphisms and for evidence of altered expression oF RB protein by immunohistochemical staining. RESULTS All of 11 specimens from 5 patients with parathyroid carcinoma and informative DNA patterns and 1 of 19 specimens from 19 patients with parathyroid adenoma and informative DNA patterns lacked an RB allele. Fourteen of 16 specimens (88 percent) from the nine patients with carcinoma had abnormal expression of RB protein (a complete or predominant absence of nuclear staining for the protein). None of the 19 adenomas, including the tumor with loss of an RB allele, had unequivocally abnormal staining for RB protein. CONCLUSIONS Inactivation of the RB gene is common in parathyroid carcinoma and is likely to be an important contributor to its molecular pathogenesis. The presence of such inactivation may help to distinguish benign from malignant parathyroid disease and may have useful diagnostic, prognostic, and therapeutic implications.

Mantle cell lymphoma: correlation of clinical outcome and biologic features with three histologic variants.

PURPOSE Clinical data and histologic material were retrospectively analyzed in 46 cases of previously untreated mantle cell lymphoma (MCL) to more fully characterize the clinical response pattern of these lymphomas and to determine whether growth pattern significantly affected clinical outcome. MATERIALS AND METHODS The histologic pattern was classified as diffuse (61%), nodular (13%), and mantle zone (26%) in accordance with stated criteria. RESULTS Bone marrow infiltration was detected in 69% of cases; the frequency of involvement correlated with histologic pattern, being most common in diffuse variants and least common in mantle zone variants. Other sites of extranodal involvement were observed in 50% of cases. Cyclin-D1 staining revealed nuclear positivity in 23 of 25 patients (92%) and no difference was observed between the various histologic patterns. Rearrangement at the bcl-1 major translocation cluster (MTC) was detected in seven of 21 cases, without regard for histologic pattern. Complete response rates to doxorubicin-based regimens showed a striking correlation with histologic pattern. Seventy-three percent of patients with a mantle zone pattern attained a complete response compared with only 25% of patients with a nodular pattern and 19% with a diffuse pattern. Three-year survival rates were 100%, 50%, and 55% for patients with mantle zone, nodular, and diffuse histologic patterns, respectively. CONCLUSION We conclude that (1) diffuse and nodular MCL are associated with a poor treatment response and a poor overall survival rate; (2) the mantle zone variant exhibits the clinical attributes of a low-grade lymphoma; and (3) the poor survival rates of patients with nodular and diffuse MCL suggest that these variants be classified as intermediate-grade lymphomas. However, the trend of the time to treatment failure curve does not indicate that current regimens can cure MCL.

Superimposed histologic and genetic mapping of chromosome 9 in progression of human urinary bladder neoplasia: implications for a genetic model of multistep urothelial carcinogenesis and early detection of urinary bladder cancer

The evolution of alterations on chromosome 9, including the putative tumor suppressor genes mapped to the 9p21-22 region (the MTS genes), was studied in relation to the progression of human urinary bladder neoplasia by using whole organ superimposed histologic and genetic mapping in cystectomy specimens and was verified in urinary bladder tumors of various pathogenetic subsets with long-term follow-up. The applicability of chromosome 9 allelic losses as non-invasive markers of urothelial neoplasia was tested on voided urine and/or bladder washings of patients with urinary bladder cancer. Although sequential multiple hits in the MTS locus were documented in the development of intraurothelial precursor lesions, the MTS genes do not seem to represent a major target for p21-23 deletions in bladder cancer. Two additional tumor suppressor genes involved in bladder neoplasia located distally and proximally to the MTS locus within p22-23 and p11-13 regions respectively were identified. Several distinct putative tumor suppressor gene loci within the q12-13, q21-22, and q34 regions were identified on the q arm. In particular, the pericentromeric q12-13 area may contain the critical tumor suppressor gene or genes for the development of early urothelial neoplasia. Allelic losses of chromosome 9 were associated with expansion of the abnormal urothelial clone which frequently involved large areas of urinary bladder mucosa. These losses could be found in a high proportion of urothelial tumors and in voided urine or bladder washing samples of nearly all patients with urinary bladder carcinoma.

Level of retinoblastoma protein expression correlates with p16 (MTS-1/INK4A/CDKN2) status in bladder cancer

Recent studies have shown that patients whose bladder cancer exhibit overexpression of RB protein as measured by immunohistochemical analysis do equally poorly as those with loss of RB function. We hypothesized that loss of p16 protein function could be related to RB overexpression, since p16 can induce transcriptional downregulation of RB and its loss may lead to aberrant RB regulation. Conversely, loss of RB function has been associated with high p16 protein expression in several other tumor types. In the present study RB negative bladder tumors also exhibited strong nuclear p16 staining while each tumor with strong, homogeneous RB nuclear staining were p16 negative, supporting our hypothesis. To expand on these immunohistochemical studies additional cases were selected in which the status of the p16 encoding gene had been determined at the molecular level. Absent p16 and high RB protein expression was found in the tumors having loss of heterozygosity within 9p21 and a structural change (mutation or deletion) of the remaining p16 encoding gene allele, confirming the staining results. These results strongly support the hypothesis that the RB nuclear overexpression recently associated with poor prognosis in bladder cancer is also associated with loss of p16 function and implies that loss of p16 function could be equally deleterious as RB loss in bladder and likely other cancers.

Prediction of familial predisposition to retinoblastoma.

Retinoblastoma is a childhood cancer, predisposition to which is inherited as an autosomal dominant trait. We used restriction-fragment-length and isozymic alleles of loci on chromosome 13 in five families predisposed to retinoblastoma, to provide identification before illness of persons likely to have tumors. The likelihood of disease was predicted in two cases, and freedom from disease in three. The calculated predictive accuracy was greater than 94 percent in cases with informative loci flanking the retinoblastoma (RB1) locus, and our prediction has been fulfilled in each such instance. A case that was informative at several loci indicated the occurrence of meiotic recombination, and accurate prediction was based on data obtained with DNA markers and isozymic forms of esterase D. The calculated predictive accuracy in another case, which was informative only for loci distal to the retinoblastoma locus, was about 70 percent. This patient was expected to acquire the disease but had not done so at the age of one year, illustrating the need for more markers that are also more informative and genetically closer to the retinoblastoma locus. These studies provide the basis for prenatal and postnatal prediction of susceptibility to inherited cancer using arbitrary recombinant DNA markers. Such predictions should make genetic counseling for familial retinoblastoma more accurate and lead to earlier tumor detection and more effective therapy.

Role of tumor necrosis factor-related apoptosis-inducing ligand in interferon-induced apoptosis in human bladder cancer cells

Immunomodulators such as Bacillus Calmette-Guerin and interferon are clinically active in transitional cell carcinoma of the bladder, but their mechanisms of action remain unclear. Here we investigated the effects of IFNα on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression and apoptosis in a panel of 20 human bladder cancer cell lines. Six (30%) displayed significant DNA fragmentation in response to increasing concentrations of IFNα (10–100,000 units/mL). In these lines IFNα induced early activation of caspase-8, and DNA fragmentation was blocked by a caspase-8-selective inhibitor (IETDfmk), consistent with the involvement of death receptor(s) in cell death. IFNα stimulated marked increases in TRAIL mRNA and protein in the majority of IFN-sensitive and IFN-resistant cell lines. A blocking anti-TRAIL antibody significantly inhibited IFN-induced DNA fragmentation in four of six IFN-sensitive cell lines, confirming that TRAIL played a direct role in cell death. Bortezomib (PS-341, Velcade), a potent TRAIL-sensitizing agent, increased sensitivity to IFNα in two of the IFN-resistant cell lines that produced large amounts of TRAIL in response to IFN treatment. Our data show that IFN-induced apoptosis in bladder cancer cells frequently involves autocrine TRAIL production. Combination therapy strategies aimed at overcoming TRAIL resistance may be very effective in restoring IFN sensitivity in a subset of human bladder tumors.

Expression of p16, Rb, and cyclin D1 gene products in oral and laryngeal squamous carcinoma: biological and clinical implications.

Cyclin D1, p16, and Rb genes play a critical role in the regulation of the G1-S transition of the cell cycle and are frequently altered in several neoplastic entities. Analysis of the protein products of these genes by molecular and immunohistochemical methods provides information on their functional status and allows for the phenotypic evaluation of tumor cells. We performed Western blotting and immunohistochemical analysis on tissues from 35 primary oral and laryngeal squamous carcinoma specimens with previous molecular analysis of the p16 gene and correlated the results with relevant clinicopathologic factors. Our study shows significant concordance between Western blotting and immunostaining results for cyclin D1 (P = .01), p16 proteins (P = .01), and Rb (P = .04). Heterogeneous staining of tumor cells and the positivity of non-neoplastic host elements for Rb by immunohistochemistry contributed to the discrepancy noted in some tumors by Western blotting. Significant reciprocal relationship between p16 and Rb proteins was observed (P < .001); in most tumors, absence of p16 (89%) and detectable Rb (94%) proteins were found. Two tumors had negative cyclin D1 expression, and one third overexpressed this protein. There was a lack of correlation between cyclin D1 overexpression and the clinicopathologic factors studied. Our results indicate that the absence of p16 in most of these tumors may constitute an early tumorigenic event and that the loss of the Rb function plays a minor role in HNSC.

An improved intravesical model using human bladder cancer cell lines to optimize gene and other therapies

Orthotopic implantation of human bladder cancer cells into immunodeficient mice is an important tool for studying the biology and effects of therapy. Nevertheless, the incidence of tumor implantation and growth by transurethral instillation of the human bladder cancer cells into murine bladders has been low or not reproducible. However, using a modified intravesical technique and the human bladder cancer cell lines, KU-7 and UM-UC-2, we have been able to obtain a high and reproducible incidence of superficial bladder tumors. Furthermore, intravesical administration of the LacZ adenovirus vector resulted in significant β-galactosidase expression in these bladder tumors as well as the normal urothelium, which was associated with the removal of the glycosoaminoglycan layer. Because this modified technique produces a high incidence of superficial human tumor growth and allows the efficacy of gene transfer to be evaluated, it should be a useful model for the study of intravesical gene therapy for human bladder cancer. Cancer Gene Therapy (2000) 7, 1575–1580.

p53, Rb, and cyclin D1 expression in human oral verrucous carcinomas.

The verrucous carcinoma (VC), a tumor with low grade malignancy, appears to be associated with tobacco and human papillomavirus. The pathobiology of these tumors has not been extensively studied, and molecular genetic alterations have not been reported. In this study we investigated by immunohistochemistry the expression of p53, Rb, and cyclin D1 in a series of well‐defined oral VC. Changes in the expression of these genes have been commonly reported in a variety of human tumors.