Novel PLA2G4C polymorphism as a molecular diagnostic assay for 19q loss in human gliomas

Uncovering Driver DNA Methylation Events in Nonsmoking Early Stage Lung Adenocarcinoma

As smoking rates decrease, proportionally more cases with lung adenocarcinoma occur in never-smokers, while aberrant DNA methylation has been suggested to contribute to the tumorigenesis of lung adenocarcinoma. It is extremely difficult to distinguish which genes play key roles in tumorigenic processes via DNA methylation-mediated gene silencing from a large number of differentially methylated genes. By integrating gene expression and DNA methylation data, a pipeline combined with the differential network analysis is designed to uncover driver methylation genes and responsive modules, which demonstrate distinctive expressions and network topology in tumors with aberrant DNA methylation. Totally, 135 genes are recognized as candidate driver genes in early stage lung adenocarcinoma and top ranked 30 genes are recognized as driver methylation genes. Functional annotation and the differential network analysis indicate the roles of identified driver genes in tumorigenesis, while literature study reveals significant correlations of the top 30 genes with early stage lung adenocarcinoma in never-smokers. The analysis pipeline can also be employed in identification of driver epigenetic events for other cancers characterized by matched gene expression data and DNA methylation data.

Progesterone and estrogen receptors: opposing prognostic indicators in meningiomas

OBJECT

The preponderance of progesterone receptors (PRs) and the scarcity of estrogen receptors (ERs) in meningiomas are well known. The expression of PRs may relate to tumor grade and recurrence. Cytogenetic abnormalities are associated with aggressive behavior, recurrence, and progression. In this study, the authors focus on the prognostic implications of hormone receptors in meningiomas to help determine the clinical and biological aggressiveness of tumors and their correlations with cytogenetic abnormalities.

METHODS

Two hundred thirty-nine patients with meningiomas were separated into three groups. Group 1 (PR-positive group) comprised patients whose meningiomas displayed expression of PRs alone. Group 2 (receptor-negative group) included patients whose lesions did not have receptors for either progesterone or estrogen. Group 3 (ER-positive group) included patients whose tumors displayed expression of ERs. Clinical and histological findings, proliferative indices, tumor recurrence, and cytogenetic findings were analyzed by performing the Fisher exact test. Compared with the receptor-negative (Group 2) and ER-positive (Group 3) groups, the PR-positive group (Group 1) had a statistically significant lower proliferative index and a smaller number of patients in whom there were aggressive histopathological findings or changes in karyotype. In Groups 1, 2, and 3, the percentages of cases with aggressive histopathological findings were 10, 31, and 33%, respectively; the percentages of cases with chromosomal abnormalities were 50, 84, and 86%, respectively; and the percentages of cases in which there initially was no residual tumor but recurrence was documented were 5, 30, and 27%, respectively. A statistically significant increase in the involvement of chromosomes 14 and 22 was identified in receptor-negative and ER-positive de novo meningiomas, when compared with the PR-positive group. Abnormalities on chromosome 19 were statistically significantly higher in receptor-negative meningiomas than in PR-positive tumors.

CONCLUSIONS

The expression of the PR alone in meningiomas signals a favorable clinical and biological outcome. A lack of receptors or the presence of ERs in meningiomas correlates with an accumulation of qualitative and quantitative karyotype abnormalities, a higher proportional involvement of chromosomes 14 and 22 in de novo tumors, and an increasing potential for aggressive clinical behavior, progression, and recurrence of these lesions. Sex hormone receptor status should routinely be studied for its prognostic value, especially in female patients, and should be taken into account in tumor grading. The initial receptor status of a tumor may change in progression or recurrence of tumor.

Oligodendroglioma: toward molecular definitions in diagnostic neuro-oncology

Oligodendroglial tumors have attracted great interest in both basic and clinical neuro-oncology over the past decade. This interest is mainly due to the clinical observation that anaplastic oligodendrogliomas and anaplastic oligoastrocytomas, in contrast to the vast majority of anaplastic astrocytomas and glioblastomas, frequently respond favorably to chemotherapy. In addition, oligodendroglial tumors are associated with longer survival times than the diffuse astrocytic gliomas. These differences in response to therapy and in prognosis have been associated with distinct genetic aberrations, in particular the frequent loss of alleles on chromosome arms 1p and 19q in oligodendroglial tumors. In addition, other genetic changes have been reported as indicators of poor response to therapy and short survival, including homozygous deletion of the CDKN2A gene at 9p21, mutation of the PTEN gene at 10q23, and amplification of the EGFR gene at 7p12. In this review we summarize the current state of the art concerning the molecular genetics of oligodendroglial tumors. A particular focus is placed on the role of molecular genetic findings in the diagnostic and prognostic assessment of these neoplasms. As a result of the recent advances in the field, we propose that clinical decisions in the management of patients with oligodendroglial tumors should be based on the combined assessment of clinical and neuroimaging features, histological classification and grading, as well as molecular genetic characteristics.