Pan‐cancer analysis of copy number changes in programmed death‐ligand 1 (PD‐L1, CD274) – associations with gene expression,mutational load,and survival

Inhibition of the PD‐L1 (CD274) – PD‐1 axis has emerged as a powerful cancer therapy that prevents evasion of tumor cells from the immune system. While immunohistochemical detection of PD‐L1 was introduced as a predictive biomarker with variable power, much less is known about copy number alterations (CNA) affecting PD‐L1 and their associations with expression levels, mutational load, and survival. To gain insight, we employed The Cancer Genome Atlas (TCGA) datasets to comprehensively analyze 22 major cancer types for PD‐L1 CNAs. We observed a diverse landscape of PD‐L1 CNAs, which affected focal regions, chromosome 9p or the entire chromosome 9. Deletions of PD‐L1 were more frequent than gains (31% vs. 12%) with deletions being most prevalent in melanoma and non‐small cell lung cancer. Copy number gains most frequently occurred in ovarian cancer, head and neck cancer, bladder cancer, cervical and endocervical cancer, sarcomas, and colorectal cancers. Fine‐mapping of the genetic architecture revealed specific recurrently amplified and deleted core regions across cancers with putative biological and clinical consequences. PD‐L1 CNAs correlated significantly with PD‐L1 mRNA expression changes in many cancer types, and tumors with PD‐L1 gains harbored significantly higher mutational load compared to non‐amplified cases (median: 78 non‐synonymous mutations vs. 40, P = 7.1e‐69). Moreover, we observed that, in general, both PD‐L1 amplifications and deletions were associated with dismal prognosis. In conclusion, PD‐L1 CNAs, in particular PD‐L1 copy number gains, represent frequent genetic alterations across many cancers, which influence PD‐L1 expression levels, are associated with higher mutational loads, and may be exploitable as predictive biomarker for immunotherapy regimens. © 2016 Wiley Periodicals, Inc.     

Biology and grading of pleomorphic xanthoastrocytoma—what have we learned about it?

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytoma predominantly affecting children and young adults. We performed comprehensive genomic characterization on a cohort of 67 patients with histologically defined PXA (n = 53, 79%) or anaplastic PXA (A‐PXA, n = 14, 21%), including copy number analysis (ThermoFisher Oncoscan, n = 67), methylation profiling (Illumina EPIC array, n = 43) and targeted next generation sequencing (n = 32). The most frequent alterations were CDKN2A/B deletion (n = 63; 94%) and BRAF p.V600E (n = 51, 76.1%). In 7 BRAF p.V600 wild‐type cases, alternative driver alterations were identified involving BRAF, RAF1 and NF1. Downstream phosphorylation of ERK kinase was uniformly present. Additional pathogenic alterations were rare, with TERT, ATRX and TP53 mutations identified in a small number of tumors, predominantly A‐PXA. Methylation‐based classification of 46 cases utilizing a comprehensive reference tumor allowed assignment to the PXA methylation class in 40 cases. A minority grouped with the methylation classes of ganglioglioma or pilocytic astrocytoma (n = 2), anaplastic pilocytic astrocytoma (n = 2) or control tissues (n = 2). In 9 cases, tissue was available from matched primary and recurrent tumors, including 8 with anaplastic transformation. At recurrence, two tumors acquired TERT promoter mutations and the majority demonstrated additional non‐recurrent copy number alterations. Methylation class was preserved at recurrence. For 62 patients (92.5%), clinical follow‐up data were available (median follow‐up, 5.4 years). Overall survival was significantly different between PXA and A‐PXA (5‐year OS 80.8% vs. 47.6%; P = 0.0009) but not progression‐free survival (5‐year PFS 59.9% vs. 39.8%; P = 0.05). WHO grade remained a strong predictor of overall survival when limited to 38 cases defined as PXA by methylation‐based classification. Our data confirm the importance of WHO grading in histologically and epigenetically defined PXA. Methylation‐based classification may be helpful in cases with ambiguous morphology, but is largely confirmatory in PXA with well‐defined morphology.     

Promoter hypermethylation inactivate tumor suppressor FAM134B and is associated with poor prognosis in colorectal cancer

The present study aims to examine promoter methylation status of FAM134B in a large cohort of patients with colorectal adenocarcinomas. The clinical significances and correlations of FAM134B promoter methylation with its expression are also analysed. Methylation‐specific high‐resolution melt‐curve analysis followed by sequencing was used to identify FAM134B promoter methylation in colorectal adenomas (N = 32), colorectal adenocarcinomas (N = 164), matched adjacent non‐neoplastic colorectal mucosae (N = 83) and colon cancer cell lines (N = 4). FAM134B expression was studied by real‐time quantitative polymerase chain reaction, immunohistochemistry, and Western blots. FAM134B promoter methylation was more frequent in adenocarcinomas (52%; 85/164) when compared to that of adenomas (28%; 9/32) and non‐neoplastic mucosae (35%; 29/83). Cancer cells exhibited higher methylation when compared to non‐neoplastic cells. FAM134B promoter methylation was inversely correlated with low FAM134B copy number and mRNA/protein expressions, whereas in‐vitro demethylation has restored FAM134B expression in colon cancer cells. FAM134B promoter methylation was associated with high histological grade (P = .025), presence of peri‐neural infiltration (P = .012), lymphovascular invasion (P = .021), lymph node metastasis (P = .0001), distant metastasis (P = .0001) and advanced pathological stages (P = .0001). In addition, FAM134B promoter methylation correlated with cancer recurrence and poor survival rates of patients with colorectal adenocarcinomas. To conclude, FAM134B promoter methylation plays a key role in regulating FAM134B expression in vitro and in vivo, which in turn contributes to the prediction of the biological aggressiveness of colorectal adenocarcinomas. Furthermore, FAM134B methylation might act as a marker in predicting clinical prognosis in patients with colorectal adenocarcinomas.     

RB1 gene in Merkel cell carcinoma: hypermethylation in all tumors and concurrent heterozygous deletions in the polyomavirus‐negative subgroup

Sequestration of the tumor suppressor retinoblastoma protein (RB) by the Merkel cell polyomavirus (MCV) is a crucial step in the pathogenesis of Merkel cell carcinoma (MCC). RB expression is frequently lost, particularly in MCV‐negative MCC tumors, through yet unknown mechanisms. We compared the genomic copy number changes of 13 MCV‐positive and 13 ‐negative MCC tumors by array comparative genomic hybridization. The analysis revealed increased genomic instability, amplification of 1p34.3–1p34.2, and losses of 11p in the absence of MCV infection. Deletions of the RB1 locus were also detected at high rates in MCV‐negative tumors. None of the tumors with heterozygous RB1 losses expressed RB in immunohistochemistry. RB1 promoter hypermethylation was studied with a methylation‐specific multiplex ligation‐dependent probe amplification technique. The RB1 promoter was methylated in all tumor specimens at CpG islands located close to the ATG start codon, albeit at low levels. The pattern of hypermethylation was similar in all MCC samples, despite RB expression, survival or MCV status. In conclusion, the frequent heterozygous losses of the RB1 locus could partly explain the decreased RB expression in MCV‐negative MCC tumors, although the effects of RB1 mutations, coinciding promoter hypermethylation and, for example, miRNA regulation, cannot be excluded.     

CD274 (PDL1) and JAK2 genomic amplifications in pulmonary squamous‐cell and adenocarcinoma patients

Aims

CD274 (PDL1) and JAK2 (9p24.1) gene amplifications have been recently described in pulmonary carcinomas in association with programmed death‐ligand 1 (PD‐L1) expression. Furthermore, PTEN loss has been explored preclinically in relation to PD‐L1 expression. Our aim was to determine whether these genomic alterations affect PD‐L1 expression levels in non‐small‐cell lung cancer.

Methods and results

PD‐L1 and PTEN expression determined by immunohistochemistry (IHC), and CD274, JAK2 and PTEN copy number alterations (CNAs) determined by fluorescence in‐situ hybridisation, were studied in 171 pulmonary carcinoma specimens. PD‐L1 expression was positive in 40 cases (23.3%), and CD274 amplification was present in 14 tumours (8.8%). Concordance between both events was found in 12 of 14 amplified cases (P = 0.0001). We found nine JAK2‐amplified cases (5.7%), seven with PD‐L1 expression (P = 0.0006). Moreover, six of the seven cases had JAK2 and CD274 coamplification (9p24.1 genomic amplification). Remarkably, the average PD‐L1 IHC score was higher in these amplified cases (230 versus 80; P = 0.001). Non‐statistical associations were observed between PD‐L1 expression and PTEN loss and PTEN deletions.

Conclusions

We describe a subset of patients (8.2%) who had 9p24.1 amplifications resulting in high expression of PD‐L1. Our results provide evidence for genomic up‐regulation of PD‐L1 expression in non‐small‐cell lung cancer.     

Enhanced expression of cathepsin L in metastatic bone tumors.

Cathepsin L is a kind of cystein proteases which are known to facilitate the invasion and metastasis of tumor cells by degrading the components of basement membrane and extracellular matrix. This study was undertaken to investigate the expression of cathepsin L by Northern blot analysis with radiolabeled cDNA specific for cathepsin L in six normal tissues, two osteosarcoma cell lines, MG-63 and Saos-2, six primary bone tumors and six metastatic bone tumors. In six normal tissues, the highest level of cathepsin L was expressed in liver with the descending order of liver > lung > thymus > ovary > kidney > esophagus. One of the two osteosarcoma cell lines established from the primary sites expressed a high level of cathepsin L mRNA. Out of six primary bone tumors, three (50%) expressed cathepsin L mRNA, while all (100%) of six metastatic bone tumors expressed the mRNA. These results demonstrating the higher frequency of expression of cathepsin L in metastatic bone tumors suggest that cathepsin L may participate in tumor invasion and metastasis.     

Multiple DICER1‐related tumors in a child with a large interstitial 14q32 deletion

Germ‐line interstitial deletions involving the 14q32 chromosomal region, resulting in 14q32 deletion syndrome, are rare. DICER1 is a recently described cancer‐predisposition gene located at 14q32.13. We report the case of a male child with a ～5.8 Mbp 14q32.13q32.2 germ‐line deletion, which included the full DICER1 locus. We reviewed available clinical and pathological material, and conducted genetic analyses. In addition to having congenital dysmorphic features, the child developed multiple DICER1 syndrome‐related tumors before age 5 y: a pediatric cystic nephroma (pCN), a ciliary body medulloepithelioma (CBME), and a small lung cyst (consistent with occult pleuropulmonary blastoma Type I/Ir cysts seen in DICER1 mutation carriers). He also developed a cerebral spindle‐cell sarcoma with myogenous differentiation. Our investigations revealed that the deletion encompassed 31 protein‐coding genes. In addition to the germ‐line DICER1 deletion, somatic DICER1 RNase IIIb mutations were found in the CBME (c.5437G > A, p.E1813K), pCN (c.5425G > A, p.G1809R), and sarcoma (c.5125G > A, p.D1709N). The sarcoma also harbored a somatic TP53 mutation: c.844C > T, p.R282W. Additional copy number alterations were identified in the CBME and sarcoma using an OncoScan array. Among the 8 cases with molecularly‐defined 14q32 deletions involving DICER1 and for whom phenotypic information is available, our patient and one other developed DICER1‐related tumors. Biallelic DICER1 mutations have not previously been reported to cause cerebral sarcoma, which now may be considered a rare manifestation of the DICER1 syndrome. Our study shows that DICER1‐related tumors can occur in children with 14q32 deletions and suggests surveillance for such tumors may be warranted.     

PD‐L1 expression and deficient mismatch repair in ductal adenocarcinoma of the prostate

This study aimed to investigate the expression of programmed death receptor ligand 1 (PD‐L1) and deficient mismatch repair (dMMR) in ductal adenocarcinoma of the prostate. A tissue microarray of 32 ductal and 42 grade‐matched acinar adenocarcinomas was used. Slides were stained for PD‐L1, PD‐L2, MMR proteins, CD4 and CD8. PD‐L1 expression in tumor cells was only seen in 3% (1/34) of ductal and 5% (2/42) of acinar adenocarcinomas (p = 1.0), while PD‐L1 expression in tumor‐infiltrating immune cells was seen in 29% (10/34) of ductal and 14% (6/42) of acinar adenocarcinomas (p = 0.16). dMMR, as defined by loss of one or more of the MMR proteins, was identified in 5% (4/73) of cases, including 1 ductal and 3 acinar adenocarcinomas. There was a suggested association between infiltration of CD8+ lymphocytes and ductal subtype (p = 0.04) but not between CD4+ lymphocytes and tumor type (p = 0.28). The study shows that both dMMR and PD‐L1 expression is uncommon in tumor cells of both ductal and acinar adenocarcinoma of the prostate, while PD‐L1 expression in tumor‐infiltrating immune cells is a more common finding.     

Discordance between anaplastic lymphoma kinase status in primary non‐small‐cell lung cancers and their corresponding metastases

Aims: The anaplastic lymphoma kinase gene (ALK) has attracted considerable attention as a potential molecular target in non‐small‐cell lung cancer (NSCLC). However, it is unclear whether ALK alterations are acquired during the metastatic progression of NSCLC. Methods and results: ALK status and ALK expression were evaluated in a series of 67 primary NSCLCs and their corresponding metastatic lesions using fluorescence in‐situ hybridization and immunohistochemistry. ALK rearrangement was detected in 7.5% (5/67) of the primary tumours and in 9.0% (6/67) of the metastases (P < 0.001). ALK copy number gain (CNG) was detected in 1.5% (1/67) of the primary tumours and in 35.8% (24/67) of the metastases. Whereas ALK rearrangement was detected only in adenocarcinomas, CNG was identified in various histological subtypes of NSCLC. ALK expression was detected in 11.9% (8/67) of the primary tumours and in 25.4% (17/67) of the metastatic lesions. Conclusions: ALK alteration and ALK expression can be acquired during metastatic progression in NSCLC, and ALK CNG is associated with ALK expression.     

High‐resolution genomic analysis suggests the absence of recurrent genomic alterations other than SMARCB1 aberrations in atypical teratoid/rhabdoid tumors

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare malignant pediatric brain tumor characterized by genetic alterations affecting the SMARCB1 (hSNF5/INI1) locus in chromosome band 22q11.2. To identify potential additional genetic alterations, high‐resolution genome‐wide analysis was performed using a molecular inversion probe single‐nucleotide polymorphism (MIP SNP) assay (Affymetrix OncoScan formalin‐fixed paraffin‐embedded express) on DNA isolated from 18 formalin‐fixed paraffin‐embedded archival samples. Alterations affecting the SMARCB1 locus could be demonstrated by MIP SNP in 15 out of 16 evaluable cases (94%). These comprised five tumors with homozygous deletions, six tumors with heterozygous deletions, and four tumors with copy number neutral loss of heterozygosity (LOH) involving chromosome band 22q11.2. Remarkably, MIB SNP analysis did not yield any further recurrent chromosomal gains, losses, or copy neutral LOH. On MIP SNP screening for somatic mutations, the presence of a SMARCB1 mutation (c.472C>T p.R158X) was confirmed, but no recurrent mutations of other cancer relevant genes could be identified. Results of fluorescence in situ hybridization, multiplex ligation‐dependent probe amplification, and SMARCB1 sequencing were highly congruent with that of the MIP SNP assay. In conclusion, these data further suggest the absence of recurrent genomic alterations other than SMARCB1 in AT/RT. © 2012 Wiley Periodicals, Inc.     

Distribution of vitamin B12 R-binder in lung tumors. Implications for cell differentiation

Expression of vitamin B12 R-binder, a specific binding protein for vitamin B12, was studied immunohistochemically in normal lung tissues and 107 lung tumors of various types. In normal tissues, vitamin B12 R-binder (R-binder) expression was restricted to the mucous cells of bronchial or bronchiolar epithelium and submucosal glands as well as to nonciliated bronchiolar (Clara) cells. Among lung carcinomas, 38% of squamous cell carcinomas, 42% of adenocarcinomas and 23% of large cell carcinomas showed positive staining for R-binder whereas small cell carcinomas did not. These findings offer the possibility that a majority of the histologic types of lung carcinoma have common histogenetical characteristics with mucous or Clara cells. Of the bronchial gland tumors, R-binder could be detected in a mucoepidermoid carcinoma but not in adenoid cystic carcinomas. Epithelial components in both pulmonary blastomas and hamartomas showed a reactivity for R-binder, suggesting that these tumors contained components composed of cells with bronchiolar cell differentiation. The immunohistochemical examination of lung tumors, using anti-R-binder antibody, may have some implications in the cell differentiation of lung tumors.     

Recurrent somatic loss of TNFRSF14 in classical Hodgkin lymphoma

Investigation of the genetic lesions underlying classical Hodgkin lymphoma (CHL) has been challenging due to the rarity of Hodgkin and Reed‐Sternberg (HRS) cells, the pathognomonic neoplastic cells of CHL. In an effort to catalog more comprehensively recurrent copy number alterations occurring during oncogenesis, we investigated somatic alterations involved in CHL using whole‐genome sequencing‐mediated copy number analysis of purified HRS cells. We performed low‐coverage sequencing of small numbers of intact HRS cells and paired non‐neoplastic B lymphocytes isolated by flow cytometric cell sorting from 19 primary cases, as well as two commonly used HRS‐derived cell lines (KM‐H2 and L1236). We found that HRS cells contain strikingly fewer copy number abnormalities than CHL cell lines. A subset of cases displayed nonintegral chromosomal copy number states, suggesting internal heterogeneity within the HRS cell population. Recurrent somatic copy number alterations involving known factors in CHL pathogenesis were identified (REL, the PD‐1 pathway, and TNFAIP3). In eight cases (42%) we observed recurrent copy number loss of chr1:2,352,236‐4,574,271, a region containing the candidate tumor suppressor TNFRSF14. Using flow cytometry, we demonstrated reduced TNFRSF14 expression in HRS cells from 5 of 22 additional cases (23%) and in two of three CHL cell lines. These studies suggest that TNFRSF14 dysregulation may contribute to the pathobiology of CHL in a subset of cases. © 2015 Wiley Periodicals, Inc.     

Expression of surfactant associated protein-A and Clara cell 10 kilodalton mRNA in neoplastic and non-neoplastic human lung tissue as detected by in situ hybridization.

Two markers for the progenitor cells of peripheral airways and their tumors are the 10 kilodalton (kd) Clara cell protein and the major surfactant associated protein-A (SP-A). We used the RNA-RNA in situ hybridization technique to study expression of the genes encoding these proteins at the cellular level in 19 pairs of non-neoplastic and neoplastic tissues from resected human lungs. Our results show that in non-neoplastic lung tissue, the Clara 10 kd protein gene was expressed in nonciliated cells of both bronchial and bronchiolar epithelium, indicating that, in contrast to previous assumptions, cells with Clara cell-like differentiation in humans may not be restricted to bronchiolar cells. The incidence of Clara 10 kd protein gene expression, as detected in lung carcinomas (1 out of 19 cases positive) was less than expected based on previous ultrastructural reports. The SP-A gene was strongly expressed in normal alveolar type II cells in non-neoplastic lung and, at higher levels, in hyperplastic cells. In addition, SP-A mRNA expression was observed in scattered bronchial and bronchiolar epithelial cells in 40% of the airways examined. Five out of 17 lung tumors, all of which were adenocarcinomas, were positive for SP-A expression, albeit generally less intense than type II cells. This expression was seen in carcinomas with papillolepidic as well as solid and glandular growth patterns. Our findings provide new insights into the peripheral airway cell differentiation.     

Cathepsin K is selectively expressed in the stroma of lung adenocarcinoma but not in bronchioloalveolar carcinoma. A useful marker of invasive growth

Lung bronchioalveolar carcinomas (BACs) are noninvasive tumors showing lepidic growth and excellent prognosis, whereas all the other variants of adenocarcinoma are invasive tumors with a worse prognosis. The identification of minimal invasive foci in adenocarcinoma, therefore, is of prognostic relevance. A series of 68 pulmonary tumors, including 40 acinar/papillary adenocarcinomas, 18 adenocarcinomas of the mixed subtype, and 10 BACs was tested by immunohistochemical analysis for cathepsin K expression, a proteinase involved in bone and extracellular matrix remodeling. Cathepsin K was produced by epithelial tumor cells in most invasive adenocarcinomas and, interestingly, by macrophages and fibroblasts in the stroma of invasive adenocarcinomas but not of BACs (P < .001). Our findings suggest pathogenetic implications of cathepsin K in the mechanisms of tumor invasiveness in lung carcinoma; in addition, cathepsin K immunodetection may be a valuable adjunct in the correct classification of pulmonary adenocarcinomas, especially in small sclerosing BACs and mixed adenocarcinoma subtypes with minimal infiltrative growth.     

Epigenetic silencing of miR‐200c in breast cancer is associated with aggressiveness and is modulated by ZEB1

Loss of expression of miR‐200 family members has been implicated in cellular plasticity, a phenomenon that accounts for epithelial‐to‐mesenchymal transition (EMT) and stem‐like features of many carcinomas and is considered a major cause of tumor aggressiveness and drug resistance. Nevertheless, the mechanisms of miR‐200 downregulation in breast cancer are still largely unknown. Here we show that miR‐200c expression inversely correlates with miR‐200c/miR‐141 locus methylation in triple‐negative breast tumors (TNBC). Importantly, low levels of miR‐200c expression and high levels of miR‐200c/miR‐141 locus methylation associated with lymph node metastasis. Moreover, miR‐200c/miR‐141 locus methylation was significantly related to high expression of ZEB1 in two independent TNBC series. Silencing of ZEB1 in vitro reduced miR‐200c/miR‐141 DNA methylation and, concurrently, decreased histone H3K9 trimethylation. This chromatin modifications were paralleled by an increase in the expression of both miR‐200c and E‐cadherin. Similar effects were achieved by treatment with a demethylating agent. Our data suggest that gene methylation is an important element in the regulation of the miR‐200c/ZEB1 axis and that chromatin remodeling of the miR‐200c/miR‐141 locus is affected by ZEB1 and, thus, contributes to ZEB1‐induced cellular plasticity. © 2016 Wiley Periodicals, Inc.     

Napsin A Expression in Subtypes of Thyroid Tumors: Comparison with Lung Adenocarcinomas

Napsin A is widely used in the diagnosis of lung adenocarcinoma and has also been reported to be positive in cases of thyroid carcinomas. We investigated napsin A levels through immunohistochemistry on whole sections of 210 primary thyroid tumors of various subtypes and another 41 metastatic thyroid carcinomas, and compared these with 125 primary and 25 metastatic lung adenocarcinomas. The results showed that napsin A was expressed in 23.8% thyroid tumors and 30.3% papillary thyroid carcinomas. Most cases showed a focal and weak to moderate expression. In comparison, 80.8% primary lung adenocarcinomas expressed napsin A, with mostly diffused and strong expression. For metastatic carcinomas of thyroid and lung origin, napsin A was detected in 39.0% of thyroid carcinomas in contrast to 88.0% in cases of lung adenocarcinomas. Comparisons of additional markers, TTF-1, CK7, thyroglobulin, and Pax-8 in metastatic carcinomas showed the overlapping expression of immunomarkers of TTF-1 and CK7. Thyroglobulin and Pax-8 were useful for distinguishing between metastatic carcinomas; however, Pax-8 may be a superior marker due to its higher sensitivity. The clinicopathological analysis of papillary thyroid carcinomas showed that the expression of napsin A was positively correlated with lymph node metastasis (p = 0.030). Here, we focused on the expression of napsin A in thyroid tumors and compared it with that in lung adenocarcinomas. The expression of napsin A is common in thyroid tumors and the combined expression of napsin A and TTF-1 in a metastatic thyroid carcinoma is a cause for concern due to chances of misdiagnosis as lung adenocarcinoma.

     

c-myc copy number gains in bladder cancer detected by fluorescence in situ hybridization.

Amplification and overexpression of c-myc have been suggested as prognostic markers in human cancer. To assess the role of c-myc gene copy number alterations in bladder cancer, 87 bladder tumors were examined for c-myc aberrations by fluorescence in situ hybridization. Dual labeling hybridization with a repetitive pericentromeric probe specific for chromosome 8 and a probe for the c-myc locus (at 8q24) was performed to analyze c-myc copy number in relation to chromosome 8 copy number on a cell by cell basis. A clear-cut c-myc amplification (up to 40 to 150 copies per cell) was found in 3 tumors. There was a low level c-myc copy number increase in 32 of the remaining 84 tumors. There was no association of low level c-myc copy number increase with c-myc protein overexpression. This suggests that a c-myc gene copy number gain as detected by fluorescence in situ hybridization does not necessarily reflect a disturbed c-myc gene function but may indicate a structural chromosome 8 abnormality including gain of distal 8q. The strong association of low level c-myc (8q) gains with tumor grade (P < 0.0001), stage (P < 0.0001), chromosome polysomy (P < 0.0001), p53 protein expression (P = 0.0019), p53 deletion (P = 0.0403), and tumor cell proliferation (Ki67 labeling index; P = 0.0021) is consistent with a role of chromosome 8 alterations in bladder cancer progression.