| 1. |
- Hägerstrand, Daniel, et al.
(author)
-
Gene expression analyses of grade II gliomas and identification of rPTPbeta/ as a candidate oligodendroglioma marker
- 2008
-
In: Neuro-Oncology. - : Oxford University Press (OUP). - 1522-8517 .- 1523-5866. ; 10:1, s. 2-9
-
Journal article (peer-reviewed)abstract
- Grade 11 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 rPT beta/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 rPTP beta/zeta staining. In summary, this study demonstrates a correlation between gene expression pattern and histological subtype in grade 11 gliomas. Furthermore, the results from the immunohistochemical analyses of rPTP beta/zeta expression should prompt further evaluation of this protein as a novel oligodendroglioma marker.
|
|
| 2. |
- Qu, Mingqi, et al.
(author)
-
Genetically distinct astrocytic and oligodendroglial components in oligoastrocytomas
- 2007
-
In: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 113:2, s. 129-136
-
Journal article (peer-reviewed)abstract
- 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.
|
|
| 3. |
- Simonsson, Martin, et al.
(author)
-
Epidermal keratinocyte loss in response to daily 2 Gy fractions for 5 weeks of radiotherapy is associated with DSB-foci, growth arrest, apoptosis and lack of accelerated repopulation
-
Other publication (other academic/artistic)abstract
- Background and purpose: Tissue-sparing due to repopulation is expected to occur in epithelial cell populations during a course of fractionated radiotherapy (RT). Recently, we established, in the clinical setting of RT, the dose response relationship of subtherapeutic doses in terms of epidermal keratinocyte loss in the basal layer throughout 7 weeks of RT. Surprisingly, in the case of daily dose fractions of 1.10Gy, the keratinocyte loss per dose unit increases over the last 4 weeks of the treatment period rather than being constant or decreasing. The aim of the present study is to elaborate on the issue of germinal keratinocyte response to daily dose fractions of 2.0Gy for 5 weeks. Here, we present assessments of keratinocyte loss, DSB foci, growth arrest, mitosis and apoptosis using methods earlier described by us. Materials and Methods: In total 240 skin punch biopsies, collected from 31 breast cancer patients, before, during and after postmastectomy radiotherapy given to the thoracic wall with daily 2.0Gy fractions for 5 weeks, were investigated. The dose response for basal keratinocyte density of the interfollicular epidermis was determined. The DNA damage response of keratinocytes was studied by immunostaining for molecular markers of DNA DSBs, growth arrest, mitosis and cell death using 53BP1, p21, phospho-H3 and γH2AX (apoptosis), respectively. The stainings of keratinocytes were counted manually or by digital image analysis. Results: The dose-response relationship for the loss of basal keratinocytes over 5 weeks of RT revealed a biphasic shape. An initial radioresistant phase was followed by an increase in radiosensitivity in the second part of RT. The rate of keratinocyte loss reflected the significant changes determined by 53BP1 and γH2AX foci 30 minutes after dose fractions over the treatment period. The highest induction of DSB foci per cell was observed towards the end of treatment. The increase in the fraction of p21 stained cells was also more prominent during the second half of the treatment as compared to the first period of RT. The apoptotic frequency was generally low but increased dramatically towards the end of RT. The mitotic cell number was significantly suppressed over 5 weeks, and did not recover during the weekend treatment-gaps. Notably, the mitotic rate increased more than threefold compared to unexposed skin, 2 weeks after the end of RT, followed by a rapid decline one week later. Conclusion: The dose response for germinal keratinocyte loss as a result of daily dose fractions of 2.0Gy over 5 weeks treatment deviates significantly from an exponential curve fit. The effectiveness of each dose fraction was less in the first half of the treatment when compared with the second half. No accelerated repopulation could be revealed over the 5 weeks, but was evident after completion of radiotherapy. The changes in keratinocyte response were associated with changes in induction of DSB foci and p21 protein expression, as well as apoptotic events over the treatment period. In particular, we highlight the existence of pre-mitotic apoptosis, which increased significantly towards the end of 5 weeks RT. These findings suggest that it is necessary to reconsider the current conceptions regarding DNA repair, cell-cycle redistribution and repopulation of normal epithelial cells to a long-lasting courses of fractionated radiotherapy.
|
|
| 4. |
- Turesson, Ingela, et al.
(author)
-
A low-dose hypersensitive keratinocyte loss in response to fractionated radiotherapy is associated with growth arrest and apoptosis.
- 2010
-
In: Radiotherapy and oncology. - : Elsevier BV. - 1879-0887 .- 0167-8140. ; 94:1, s. 90-101
-
Journal article (peer-reviewed)abstract
- 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.
|
|
| 5. |
|
|
