Proteomic Profiles Associated With Postsurgical Progression in Nonfunctioning Pituitary Adenomas.

CONTEXT: There is a lack of reliable biomarkers capable of predicting postoperative tumor progression of nonfunctioning pituitary adenomas (NFPAs). OBJECTIVE: To discover proteomic profiles associated with postoperative tumor progression in patients with NFPAs. This was a case-controlled exploratory study at a tertiary university hospital. Tissue samples were obtained from 46 patients with residual tumor following surgery for NFPAs of gonadotroph lineage. Two patient groups were compared: patients requiring reintervention due to residual tumor progression (cases; reintervention group, n = 29) and patients with a residual tumor showing no progression for a minimum of 5 years (controls; radiologically stable group, n = 17). Differentially expressed proteins (DEPs) between patient groups were measured. RESULTS: Global quantitative proteomic analysis identified 4074 proteins, of which 550 were differentially expressed between the 2 groups (fold change >80%, false discovery rate-adjusted P ≤ .05). Principal component analysis showed good separation between the 2 groups. Functional enrichment analysis of the DEPs indicated processes involving translation, ROBO-receptor signaling, energy metabolism, mRNA metabolism, and RNA splicing. Several upregulated proteins in the reintervention group, including SNRPD1, SRSF10, SWAP-70, and PSMB1, are associated with tumor progression in other cancer types. CONCLUSION: This is the first exploratory study analyzing proteomic profiles as markers of postoperative tumor progression in NFPAs. The findings clearly showed different profiles between tumors with indolent postoperative behavior and those with postoperative tumor progression. Both enriched pathways involving DEPs and specific upregulated proteins have previously been associated with tumor aggressiveness. These results suggest the value of proteomic profiling for predicting tumor progression in patients with NFPAs.

Genome-wide DNA Methylation Differences in Nonfunctioning Pituitary Adenomas With and Without Postsurgical Progression.

CONTEXT: Tumor progression in surgically treated patients with nonfunctioning pituitary adenomas (NFPAs) is associated with excess mortality. Reliable biomarkers allowing early identification of tumor progression are missing. OBJECTIVE: To explore DNA methylation patterns associated with tumor progression in NFPA patients. METHODS: This case-controlled exploratory trial at a university hospital studied patients who underwent surgery for NFPA that had immunohistochemical characteristics of a gonadotropinoma. Cases included patients requiring reintervention due to tumor progression (reintervention group, n = 26) and controls who had a postoperative residual tumor without tumor progression for at least 5 years (radiologically stable group, n = 17). Genome-wide methylation data from each tumor sample were analyzed using the Infinium MethylationEPIC BeadChip platform. RESULTS: The analysis showed that 605 CpG positions were significantly differently methylated (differently methylated positions, DMPs) between the patient groups (false discovery rate adjusted P value < 0.05, beta value > 0.2), mapping to 389 genes. The largest number of DMPs were detected in the genes NUP93 and LGALS1. The 3 hypomethylated DMPs and the 3 hypermethylated DMPs with the lowest P values were all significantly (P < 0.05) and individually associated with reintervention-free survival. One of the hypermethylated DMPs with the lowest P value was located in the gene GABRA1. CONCLUSION: In this exploratory study, DNA methylation patterns in NFPA patients were associated with postoperative tumor progression requiring reintervention. The DMPs included genes that have been previously associated with tumor development. Our study is a step toward finding epigenetic signatures to predict tumor progression in patients with NFPA.

MCM7 as a marker of postsurgical progression in non-functioning pituitary adenomas.

OBJECTIVE: Current markers predicting tumour progression of pituitary adenomas after surgery are insufficient. Our objective was to investigate if minichromosome maintenance protein 7 (MCM7) expression predicts tumour progression in non-functioning pituitary adenomas (NFPAs). METHODS: In a cohort study of surgically treated NFPAs, two groups with distinctly different behaviour of a residual tumour were selected: one group requiring reintervention due to tumour progression (reintervention group, n = 57) and one with residual tumours without progression (radiologically stable group, n = 40). MCM7, Ki-67, oestrogen receptor-α expression, mitotic index and tumour subtype were assessed by immunohistochemistry, and their association with tumour progression requiring reintervention was analysed. RESULTS: Median (IQR) MCM7 expression was 7.4% (2.4-15.2) in the reintervention group compared with 2.0% (0.6-5.3) in the radiologically stable group (P <0.0001). Cox regression analysis showed an association between high (>13%) MCM7 expression and reintervention (HR: 3.1; 95% CI:1.7-5.4; P = 0.00012). The probability for reintervention within 6 years for patients with high MCM7 was 93%. Ki-67 expression >3% (P = 0.00062), age ≤55 years (P = 0.00034) and mitotic index≥1 (P = 0.024) were also associated with reintervention. Using a receiver operating characteristics curve, a predictive model for reintervention with all the above predictors yielded an area under the curve of 82%. All eight patients with both high MCM7 and high Ki-67 needed reintervention. CONCLUSION: This cohort study shows that expression of MCM7 is a predictor for clinically significant postoperative tumour progression. Together with age, Ki-67 and mitotic index, MCM7 might be of added value as a predictive marker when managing patients with NFPA after surgery.

Lowered Expression of Tumor Suppressor Candidate MYO1C Stimulates Cell Proliferation, Suppresses Cell Adhesion and Activates AKT.

Myosin-1C (MYO1C) is a tumor suppressor candidate located in a region of recurrent losses distal to TP53. Myo1c can tightly and specifically bind to PIP2, the substrate of Phosphoinositide 3-kinase (PI3K), and to Rictor, suggesting a role for MYO1C in the PI3K pathway. This study was designed to examine MYO1C expression status in a panel of well-stratified endometrial carcinomas as well as to assess the biological significance of MYO1C as a tumor suppressor in vitro. We found a significant correlation between the tumor stage and lowered expression of MYO1C in endometrial carcinoma samples. In cell transfection experiments, we found a negative correlation between MYO1C expression and cell proliferation, and MYO1C silencing resulted in diminished cell migration and adhesion. Cells expressing excess of MYO1C had low basal level of phosphorylated protein kinase B (PKB, a.k.a. AKT) and cells with knocked down MYO1C expression showed a quicker phosphorylated AKT (pAKT) response in reaction to serum stimulation. Taken together the present study gives further evidence for tumor suppressor activity of MYO1C and suggests MYO1C mediates its tumor suppressor function through inhibition of PI3K pathway and its involvement in loss of contact inhibition.

Incompletely penetrant PKD1 alleles mimic the renal manifestations of ARPKD.

Autosomal dominant polycystic kidney disease (ADPKD), caused by mutation in PKD1 or PKD2, is usually an adult-onset disorder but can rarely manifest as a neonatal disease within a family characterized by otherwise typical ADPKD. Coinheritance of a hypomorphic PKD1 allele in trans with an inactivating PKD1 allele is one mechanism that can cause early onset ADPKD. Here, we describe two pedigrees without a history of cystic kidney disease that each contain two patients with onset of massive PKD in utero. The presentations were typical of autosomal recessive PKD (ARPKD) but they were not linked to the known ARPKD gene, PKHD1. Mutation analysis of the ADPKD genes provided strong evidence that both families inherited, in trans, two incompletely penetrant PKD1 alleles. These patients illustrate that PKD1 mutations can manifest as a phenocopy of ARPKD with respect to renal involvement and highlight the perils of linkage-based diagnostics in ARPKD without positive PKHD1 mutation data. Furthermore, the phenotypic overlap between ARPKD and these patients resulting from incomplete penetrant PKD1 alleles support a common pathogenesis for these diseases.

Oncostatin M-induced genes in human astrocytomas.

Oncostatin M (OSM) is a member of the interleukin-6 (IL-6) cytokine family and known to be induced in the nervous system as a result of cell stress. OSM is expressed in most human brain tumors, but the effects on tumor cells are unclear. The cytokine is known to activate the JAK/STAT signaling pathway by binding to its receptors gp130/OSMbeta or gp130/LIFRbeta and thereby initiating activation or suppression of a number of STAT target genes. The objective of the study was to identify OSM-regulated genes that could help in understanding the function of OSM in glioma cells. The glioma cell line, U1242MG was stimulated by OSM and the gene expression patterns were analyzed by microarray. In total, nineteen differentially expressed genes were selected due to high intensity, level of up/down-regulation and biological functions. The differentially expressed genes were verified using quantitative PCR. Additional validation of the confirmed OSM-induced proteins was performed in human astrocytoma tissues by immunohistochemistry. Among the up-regulated genes were CHI3L1, PLAU, MT2A and EPAS1. These genes are known to be involved in cell matrix remodeling, migration, proliferation control and angiogenesis. The results suggest that OSM induces genes that might contribute to the development and progression of astrocytomas.

Cytogenetic and spectral karyotype analyses of benign and malignant cartilage tumours.

To date, there have been few studies published on benign and malignant cartilage tumours using high resolution molecular cytogenetic techniques such as spectral karyotyping (SKY). In this study we have used a combination of chromosome banding, SKY and FISH to characterize the chromosomal pattern in 18 benign and malignant cartilage tumours and one small cell osteosarcoma with mesenchymal chondrosarcoma-like features. Clonal structural and/or numerical aberrations were detected in 14 of these tumours. All chondroblastomas and the chondromyxoid fibroma had diploid or near-diploid karyotypes with often relatively simple karyotypes. Although no consistent abnormalities were detected in the chondroblastomas, recurrent breakpoints were found at 2q35, 3q21-23, and 18q21. The chondromyxoid fibroma had an inv(6)(p25q13) as the sole anomaly, suggesting that this is a primary abnormality characteristic of this entity. The karyotypic findings in the chondrosarcomas were, as a rule, more complex than those in the benign tumours. A typical feature was the frequent occurrence of unbalanced rearrangements leading to genomic imbalances with losses and gains of certain chromosomes or chromosome regions. The following breakpoints were recurrent: Xq21, 6p10, 9p13, 20p11 and 22q11-12. Despite the use of high-resolution molecular cytogenetic techniques, we were not able to identify any consistent abnormalities in chondrosarcomas, suggesting that tumour-specific chromosome changes are not likely to be found in this group of tumours.

Studies on the molecular pathogenesis of extraskeletal myxoid chondrosarcoma-cytogenetic, molecular genetic, and cDNA microarray analyses.

Extraskeletal myxoid chondrosarcomas (EMCs) are characterized by recurrent chromosome translocations resulting in fusions of the nuclear receptor TEC to various NH(2)-terminal partners. Here we describe the phenotypic, cytogenetic, and molecular genetic characteristics of a series of 10 EMCs. Using spectral karyotyping and fluorescence in situ hybridization, clonal chromosome abnormalities were detected in all but one tumor. A t(9;22)(q22;q12) translocation was found in three cases; a del(22)(q12-13)in one case; and variant translocations, including t(9;17)(q22;q11-12), t(7;9;17)(q32;q22;q11), and t(9;15)(q22;q21), were detected in one case each. Recurrent, secondary abnormalities, including trisomy 1q, 7, 8, 12, and 19, were found in seven tumors. All tumors contained translocation-generated or cryptic gene fusions, including EWS-TEC (five cases, of which one was a novel fusion), TAF2N-TEC (four cases), and TCF12-TEC (one case). cDNA microarray analysis of the gene expression patterns of two EMCs and a myxoid liposarcoma reference tumor revealed a remarkably distinct and uniform expression profile in both EMCs despite the fact that they had different histologies and expressed different fusion transcripts. The most differentially expressed gene in both tumors was CHI3L1, which encodes a secreted glycoprotein (YKL-40) previously implicated in various pathological conditions of extracellular matrix degradation as well as in cancer. Our findings suggests that EMC exhibits a tumor-specific gene expression profile, including overexpression of several cancer-related genes as well as genes implicated in chondrogenesis and neural-neuroendocrine differentiation, thus distinguishing it from other soft tissue sarcomas.