Gene expression analyses of grade II gliomas and identification of rPTPbeta/zeta as a candidate oligodendroglioma marker.

Grade II gliomas are morphologically and clinically heterogeneous tumors for which histopathological typing remains the major tool for clinical classification. To what extent the major histological subtypes - astrocytomas, oligodendrogliomas, and oligoastrocytomas - constitute true biological entities is largely unresolved. Furthermore, morphological classification is often ambiguous and would be facilitated by specific subtype markers. In this study, 23 grade II gliomas were expression-profiled and subjected to hierarchical clustering. All six oligodendrogliomas were grouped together in one of two major clusters; a significant correlation was thus observed between gene expression and histopathological subtype. Supervised analyses were performed to identify genes differentiating oligodendrogliomas from other grade II tumors. In a leave-one-out test using 10 features for classification, 20 out of 23 tumors were correctly classified. Among the most differentially expressed genes was rPTPbeta/zeta. The expression of the rPTP beta/zeta protein in oligodendrogliomas and astrocytomas was further validated by immunohistochemistry in an independent set of tumors. All 11 oligodendrogliomas of this set displayed strong staining. In contrast, neoplastic astrocytes were mostly negative for rPTPbeta/zeta staining. In summary, this study demonstrates a correlation between gene expression pattern and histological subtype in grade II gliomas. Furthermore, the results from the immunohistochemical analyses of rPTPbeta/zeta expression should prompt further evaluation of this protein as a novel oligodendroglioma marker.

Types of human papillomavirus revealed in cervical adenocarcinomas after DNA sequencing.

In a collection of 173 cervical adenocarcinomas, the prevalence of HPV in relation to the age of women and the distribution of the various oncogenic types of HPV were evaluated. The tumour material was analysed by PCR of the HPV L1 gene followed by direct DNA sequencing and/or the polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) technique for the identification and typing of HPV. In 68% (117/173) of the adenocarcinomas, HPV was present. A significant correlation was observed between the prevalence of HPV and age: in women younger than 40 years, HPV was present in 88%, whereas in women 60 years and older, it was found in only 39% (p<0.001). Among the HPV-positive tumours, type 18 predominated (52%) followed by type 16 (35%) and type 45 (7.7%) while other oncogenic types of HPV (31 and 59) were rarely found. HPV 16 was relatively more frequent in older women but this observation was not significant (p=0.06). HPV-typing by PCR and direct DNA sequence analysis is more specific than analysis by PCR-SSCP, especially among the less frequently occurring types of HPV. Our results further show that the prevalence of HPV in women with cervical adenocarcinomas is age-related and that the most frequently occurring types of HPV are 18, followed by 16 and 45. We have concluded that the oncogenic role of HPV in cervical squamous carcinomas and adenocarcinomas is, in some respects, discrepant.

A de novo 1.13 Mb microdeletion in 12q13.13 associated with congenital distal arthrogryposis, intellectual disability and mild dysmorphism.

A girl presented with congenital arthrogryposis, intellectual disability and mild bone-related dysmorphism. Molecular workup including the NimbleGen Human CGH 2.1M platform revealed a 1.13 Mb de novo microdeletion on chromosome 12q13.13 of paternal origin. The deletion contains 33 genes, including AAAS, AMRH2, and RARG genes as well as the HOXC gene cluster. At least one gene, CSAD, is expressed in fetal brain. The deletion partially overlaps number of reported benign CNVs and pathogenic duplications. This case appears to represent a previously unknown microdeletion syndrome and possibly the first description in humans of a disease phenotype associated with copy loss of HOXC genes.

A low-dose hypersensitive keratinocyte loss in response to fractionated radiotherapy is associated with growth arrest and apoptosis.

BACKGROUND AND PURPOSE: The existence of a hypersensitive radiation response to doses below 0.5Gy is well established for many normal and tumour cell lines. There is also evidence for hypersensitive tissue responses in acute skin damage and kidney function in mice. Recently, we have identified that a hypersensitive gammaH2AX response exists in human epidermis. The aim of this study was to investigate the dose-response of basal clonogenic keratinocytes in normal skin to fractionated radiotherapy with low dose fractions. MATERIALS: Skin punch biopsies were taken before and during radiotherapy from prostate cancer patients undergoing radiotherapy with a curative intent. Areas of epidermis receiving daily fractions of approximately 0.1, 0.2, 0.45 and 1.1Gy were biopsied on the same occasion to determine dose-response for each individual patient. In total, 89 cases were assessed either at 1, 2.5, 3, 4, 5 or 6.5 weeks in the treatment course. Biopsy sampling of another 25 patients was performed from areas receiving 0.45 and 1.1Gy per fraction at regular intervals throughout the 7-week treatment period. The number of basal keratinocytes per mm of the interfollicular epidermis was determined. The DNA damage response of the basal keratinocytes was investigated by immunohistochemical staining for molecular markers of growth arrest, mitosis and cell death, using p21, phospho-H3 and gammaH2AX, respectively. The number of stained keratinocytes in the basal layer was counted manually. The p21 staining was also quantified by digital image analysis. RESULTS: The individual dose-response relationships revealed a low-dose hypersensitivity for reduction of basal keratinocytes throughout 7 weeks of radiotherapy (p<0.01). Growth arrest and cell proliferation assessed at 1 week and 6.5 weeks showed, in both cases, hypersensitive increase of p21 (p<0.01) and hypersensitive depression of mitosis (p<0.01). Manual counting and digital image analysis of p21 showed good agreement. Cell death was infrequent but increased significantly between 1 and 6.5 weeks and displayed a hypersensitive dose-response at the end of the treatment period. CONCLUSIONS: A low-dose hypersensitivity in basal skin keratinocyte reduction is present throughout 7 weeks of radiotherapy. A persistent hypersensitive growth arrest response and cell killing mediate this effect.

Genetically distinct astrocytic and oligodendroglial components in oligoastrocytomas.

Oligoastrocytomas are glial tumours consisting of a mixture of neoplastic astrocytic and oligodendroglial cells. Genetic alterations of oligoastrocytomas include loss of heterozygosity of chromosomes 1p and/or 19q (LOH 1p/19q), typically occurring in oligodendrogliomas, and mutations of TP53, frequently occurring in astrocytomas. To investigate whether these neoplastic cell types in oligoastrocytomas have different genetic profiles, we examined the two different components of oligoastrocytomas in comparison with the histological diagnosis of the specific tumour area for LOH 1p/19q and TP53 mutations by using microdissection technique. We found a variety of lost markers for 1p and 19q, and the presence of two different TP53 mutations in the tumour samples. In the majority of cases (9/11), the oligodendroglial and astrocytic components of an individual oligoastrocytoma displayed the same genotype. We present two cases of biphasic oligoastrocytomas with aberrant findings, suggesting the coexistence of genetically and morphologically distinct tumour cell clones in these tumours. In one case, the oligodendroglial part of the tumour showed LOH19q, whereas the astrocytic part showed TP53 mutation (codon 273). In another case, we found LOH 1p/19q in the oligodendroglial component, but two retained areas on chromosome 1p in the astrocytic component of the tumour. No evidence was found for the coexistence of tumour cells with the two genotypical changes within the same morphological region of one individual tumour. The two cases of biphasic oligoastrocytomas in our sample that display a different genotype in the astrocytic and oligodendroglial part of the tumour show that different components of an oligoastrocytoma may be derived from different cell clones during neoplastic transformation.