Nonrandom chromosomal aberrations and cytogenetic heterogeneity in gallbladder carcinomas

Refined pancreatobiliary UroVysion criteria and an approach for further optimization

Pancreatobiliary strictures are a common source of false negatives for malignancy detection. UroVysion is more sensitive than any other method but remains underutilized because of conflicting sensitivities and specificities due to a lack of standardized cutoff criteria and confusion in interpreting results in the context of primary sclerosing cholangitis. We set out to determine the sensitivities and specificities of UroVysion, brushing cytology, forceps biopsies, and fine needle aspiration (FNAs) for pancreatobiliary stricture malignancy detection. A retrospective review was performed of all biopsied pancreatobiliary strictures at our institution over 5 years. UroVysion was unquestionably the most sensitive method and all methods were highly specific. Sensitivity was highest while maintaining specificity when a malignant interpretation was limited to cases with 5+ cells with the same polysomic signal pattern and/or loss of one or both 9p21 signals. Only UroVysion detected the metastases and a neuroendocrine tumor. In reviewing and analyzing the signal patterns, we noticed trends according to location and diagnosis. Herein we describe our method for analyzing signal patterns and propose cutoff criteria based upon observations gleaned from such analysis.

BCL6 overexpression is associated with decreased p19 ARF expression and confers an independent prognosticator in gallbladder carcinoma

B cell lymphoma 6 (BCL6) is a protein that is vital for lymphogenesis. Its expression has been well established in lymphoma, especially in diffuse large B-cell lymphoma. Its role in carcinogenesis is less well understood. Previous study shows that BCL6 expression may regulate p19 functions, an important regulator for the p53 pathway. No prior study has attempted to evaluate the significance of BCL6 and p19(ARF) expression in a large cohort of patients with gallbladder carcinomas (GBCs). We selected 164 patients with GBC and performed immunostains for BCL6 and p19(ARF). BCL6 expression and p19(ARF) expression were evaluated using a histochemical score (H-score). We then correlated the results with various clinicopathological factors, disease-specific survival (DSS), and disease-free survival (DFS). BCL6 overexpression was significantly associated with high pT status, high TNM stage, higher histological grade (p = 0.029), vascular invasion, perineurial invasion, high Ki-67 labeling index, and low p19 expression. Importantly, BCL6 overexpression in GBC was strongly associated with worse DSS (p < 0.0001) and DFS (p < 0.0001) in the univariate analysis, and remained independently predictive of adverse outcomes (p = 0.001, hazard ratio (H.R.) = 3.098 for DSS; p = 0.002, H.R. = 2.255 for DFS). Low p19(ARF) expression was correlated with a poor DSS (p = 0.0144) and DFS (p = 0.0032) in the univariate analysis but was not prognosticatory in the multivariate analysis. In GBC, BCL6 overexpression correlated with adverse phenotypes and decreased p19(ARF) expression. BCL6 overexpression also independently predicts worse DSS and DFS, suggesting it has a role in tumorigenesis or carcinogenesis and could be a potential prognostic indicator in GBC.

CDK10 functions as a tumor suppressor gene and regulates survivability of biliary tract cancer cells

Cyclin-dependent kinase 10 (CDK10) is a member of the Cdc2 family of kinases, and has been demonstrated to be an important determinant of resistance to endocrine therapy for breast cancer. To investigate the expression and possible function of CDK10 in biliary tract cancer (BTC), we systematically examined CDK10 in tissues and cell lines. We found that expression of CDK10 was downregulated in both biliary tract tumors and cell lines. Remarkably, the expression of CDK10 correlated with clinical characteristics. Overexpression or knockdown of CDK10, respectively, inhibited or promoted cell proliferation, colony formation and migration. This suggests that CDK10 functions as a tumor suppressor gene in BTC. Overexpression of CDK10 caused malignant cells to become sensitive to chemotherapy and other hostile environments, suggesting that CDK10 functions to regulate survivability of BTC cells. We investigated the expression of six genes to resolve the mechanism. c-RAF was negatively regulated by CDK10 in both cells and specimens. Our results indicate that CDK10 plays a crucial role in the growth and survivability of biliary tract cancer, and offers a potential therapeutic target for this fatal disease.

Rsf-1/HBXAP overexpression is associated with disease-specific survival of patients with gallbladder carcinoma

Dysregulated chromatin remodeling often leads to abnormal gene expression or silencing in cells, thereby implicating tumor development and progression. As a subunit of remodeling and spacing factor (RSF) complex, Rsf-1, a novel nuclear protein with histone chaperon function, mediates ATPase-dependent chromatin remodeling and confer tumor aggressiveness in common carcinomas. We aimed, for the first time, to evaluate the Rsf-1 expression status and its associations with clinicopathological features and patient survival in a well characterized cohort of gallbladder carcinomas. Using tissue microarray-based immunohistochemistry, we assessed Rsf-1 expression in gallbladder carcinomas, yielding 88 cases undergoing surgical intervention with interpretable results. The Rsf-1 overexpression, present in 61 cases (69.3%), was significantly associated with higher histological grades (p = 0.002) and vascular invasion (p = 0.037) and marginally with non-papillary histotypes (p = 0.058). In univariate log-rank analysis, Rsf-1 overexpression was significantly predictive of disease-specific survival (p = 0.0015), which remained prognostically independent [p = 0.0191, risk ratio (RR) = 2.683], along with American Joint Committee on Cancer stages II-IV (p = 0.0265, RR = 2.102). Our findings indicate that Rsf-1 overexpression is common and associated with adverse prognosticators in gallbladder carcinomas. It may confer tumor aggressiveness through chromatin remodeling and represents a potential prognostic biomarker of gallbladder carcinomas.

Genetics of biliary tract cancers and emerging targeted therapies

Biliary tract cancers (BTC), which encompass intra- and extrahepatic cholangiocarcinomas and gallbladder carcinomas, are a genetically diverse collection of cancers. Evidence suggests distinct models of molecular and pathologic progression, and a growing body of genetics data points to a heterogeneous collection of underlying mutations in key oncogenes and tumor suppressor genes. Although tumor genetics have been used to tailor individual treatment regimens and guide clinical decision making in other cancers, these principles have not been applied in BTC. Recent clinical trials with targeted therapies seem promising, although the relationships between subsets of patients with positive responses to therapy and tumor genetics remain unexplored. Here, we summarize the molecular pathogenesis and genetics of BTCs and animal modeling and relate these to recent and ongoing clinical trials with targeted agents.

Aspects of digestive tract tumors in Down syndrome: a literature review

The purpose of this study was to describe the digestive neoplasms found in persons with Down syndrome. Due to intellectual disability, persons with Down syndrome do not convey their symptoms and pain, leading to delayed diagnosis and potentially worse outcome. It is thus important to know which organs are at risk for tumors and possible tumor risk factors. In a review of the literature, we found 13 benign tumors and 127 cancers in 1 fetus, 8 children, and 131 adults with Down syndrome. The review suggests a decreased incidence of digestive cancer, however, with a possible increased incidence of neoplasms of the pancreas and gallbladder. The distribution of cancers is distinct from that in the general population and that in persons with other intellectual disabilities who share the same life conditions, suggesting that constitutional protective factors exist. This review may allow a more specific, adapted medical follow-up for persons with Down syndrome and could help to elucidate the oncogenesis of digestive neoplasms.

Microsatellite instability and p53 expression in gallbladder carcinomas

We studied the MSI (microsatellite instability) status and p53 expression in a series of 71 gallbladder cancers (GCs) of different histologic type. All neoplasms were examined combining a microsatellite analysis at mononucleotide locus BAT-26 and an immunohistochemical study for hMSH2, hMLH1, and p53 proteins and markers of gastric and intestinal differentiation. All the 71 GCs were MSS (microsatellite stable). The p53 protein was found in 100% of undifferentiated GCs, 67% of conventional gallbladder adenocarcinomas, 50% of mucinous adenocarcinomas, and 20% GCs with squamous differentiation. All 71 MSS tumors showed presence of immunohistochemical expression of both hMLH1 and hMSH2 gene products. We concluded that microsatellite instability does not play a role in the developing of GC while p53 seems to be the most important alteration found in a large proportion of these cancers, with the only exception of mucinous and squamous gallbladder carcinomas.

Immunohistochemical and genetic analysis of non-small cell and small cell gallbladder carcinoma and their precursor lesions

Gallbladder carcinomas can be highly lethal neoplasms. Relatively little is known about the genetic abnormalities that underlie these tumors, particularly with respect to their timing in neoplastic progression. The authors evaluated 5 noninvasive dysplasias and 33 invasive gallbladder carcinomas (6 small cell carcinomas, 27 non-small cell carcinomas, of which 16 were accompanied by an in situ carcinoma component) for expression of the protein products of the p16, p53, Dpc4, and pRB tumor suppressor genes by immunohistochemistry. Neoplasms were also evaluated for the presence of activating K-ras oncogene mutations. Seventy-five percent of non-small cell gallbladder carcinomas demonstrated loss of p16 expression, whereas 63% accumulated high levels of p53. Loss of Dpc4 and pRB expression was less frequent, seen in 19% and 4% of the neoplasms, respectively. Thirty percent of neoplasms harbored activating K-ras mutations. In contrast, 100% of the small cell carcinomas of the gallbladder demonstrated inactivation of the pRB/p16 pathway; 67% showed loss of pRB expression, and the other 33% lost p16 expression. Eighty-three percent of small cell carcinomas accumulated high levels of p53, whereas loss of Dpc4 expression and activating K-ras mutations were not found. Among 15 evaluable in situ components, 13 harbored the same alterations found in the invasive component. Inactivation of p16 and p53 occur in the majority of non-small cell gallbladder carcinomas. Dpc4 inactivation and K-ras mutations occur in a significant minority of cases. pRB loss is uncommon in non-small cell gallbladder carcinoma, but virtually all small cell carcinomas inactivate the p16/pRB pathway, usually by retinoblastoma protein loss. It is noteworthy that all of these alterations occur at the level of carcinoma in situ.

Cellular and molecular biology of biliary tract cancers

Cancer of the biliary tract has been associated with point mutations of K-ras and beta-catenin proto-oncogenes; alterations of p53, p16, APC, and DPC4 tumor suppressor genes by a combination of chromosomal deletion, mutation, or methylation; and infrequently microsatellite instability. The frequencies of these alterations vary by location and race of the patient, tumor subsite, histology, and associated disease. Advances in the understanding of the genetics of this disease will help in diagnosing biliary tract cancer, screening at-risk patients, and developing therapies.

Protein kinase A and chromosomal stability

All malignant human tumors contain chromosomal rearrangements. Among them, the majority of solid tumors show chromosomal instability, caused by aberrations in chromosomal segregation during cell division. Chromosomal instability, defined as increased probability of formation of novel chromosomal mutations compared to that of normal or control cells, appears to be a feature of tumorigenesis in vivo and in vitro (in cancer cell lines). Several enzymatic kinases are involved in maintaining proper chromosomal segregation and regulating cell cycle progression. One such kinase, cAMP-dependent protein kinase A (PKA), has a functional role in many aspects of cell signaling, metabolism, and proliferation. In this review, we will discuss the potential participation of PKA in chromosomal stability. This role includes the association of PKA with the centrosome, microtubules, and the anaphase-promoting complex/cyclosome (ACP/C), all key aspects of proper chromosomal segregation.

Comparative genomic hybridization analysis of genetic aberrations associated with development and progression of biliary tract carcinomas

BACKGROUND

Little is known about genetic aberrations associated with development and progression of biliary tract carcinomas.

METHODS

To study chromosomal aberrations associated with development and progression of biliary tract carcinomas, the authors used comparative genomic hybridization to examine 50 such carcinomas.

RESULTS

Gains in part or in whole of chromosomes 1q, 8q, and 20q and losses of 5q, 8p, 9p, and 18q were detected frequently in early stage (T1/T2 classification) biliary tract carcinomas (> or = 40% of 19 early stage tumors), and they also were found in advanced stage (T3/T4 classification) tumors. In particular, loss of 9p was the most frequently observed aberration in both early stage (15 of 19; 78%) and advanced stage tumors (21 of 31; 68%). The frequencies of gains of 7p12-p14 (P < 0.003), 7p21-pter (P < 0.007), and 7q31 (P < 0.01) differed significantly between biliary tract carcinoma with and without distant metastasis. Also, gains of 5p and 19q13 and loss of 6q14-q16 were more frequent in tumors with lymph node metastasis than in those without it (P < 0.02).

CONCLUSIONS

It is likely that loss of 9p is one of the genetic aberrations critical for the development of biliary tract carcinoma, whereas gains of 5p, 7p, 7q, and 19q and loss of 6q are considered later events associated with tumor progression and are thought to confer metastatic potential to biliary tract carcinomas.

Osteoid osteomas with chromosome alterations involving 22q

Cytogenetic analysis was performed in two osteoid osteomas. In both, the modal chromosome number was 46. One of the cases presented a del(22)(q13.1) as the sole clonal chromosome alteration. The other had clonal monosomies of chromosomes 3, 6, 9, 17, 19, and 21, as well as a +del(22)(q13.1) was detected as a non-clonal chromosome alteration. There is only one osteoid osteoma reported so far showing clonal karyotypic alterations. The cytogenetic behavior of osteoid osteomas described here was different from that of the osteoid osteoma of the literature. Numerical alterations of chromosomes 3, 6, 9, 17, 19, 21 and 22 have been described in several neoplasias including bone tumors. The breakpoint of chromosome 22 involves a region where important genes for the regulation of the cell cycle have been mapped.