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PubMed2000

Prognostic significance of nuclear DNA content in chondrosarcoma.

Chondrosarcoma is the second most frequent primary malignant tumor of bone. Many of these tumors represent histopathologic borderline cases. In this study, DNA ploidy status, 2c deviation index (2cDI), and DNA malignancy grade (DNA-MG; based on the variation of nuclear DNA content of tumor cells around the normal DNA [2c] peak) were examined for their diagnostic and prognostic value in comparison with conventional histopathologic grading. Twenty-two paraffin-embedded samples were available for histopathologic investigation and for quantitative cytophotometric DNA determination of Feulgen-stained nuclei. Clinicopathologic parameters and prognosis were analyzed over a maximum follow-up period of 252 months. Nineteen of 22 (86%) chondrosarcomas showed aneuploid DNA content. 2cDI (r =.58, P <.01) and DNA-MG (r =.58; P <.01) correlate with the histopathologic grading. Significant correlation between the 2cDI (P <.01) and DNA-MG (P <.025) and the overall survival was found. Ploidy did not influence the overall survival rate. In metastasis-free patients, the 2cDI and DNA-MG gave better prognostic information than conventional histopathologic grading. When patients developed metastasis, however, histopathologic grading was the prognostic parameter of choice. Cytometric DNA measurement provide additional objective information regarding the diagnosis and prognosis of chondrosarcomas, even more than that obtained by conventional histopathologic grading, and may be helpful in planning the treatment.

Adult↗
PubMed2001

Abnormal DNA content predicts the occurrence of carcinomas in non-dysplastic oral white patches.

The majority of oral squamous cell carcinomas (OSCCs) are preceded by visible changes in the oral mucosa, most often white patches. Although the histological finding of dysplasia in oral white patches signals increased risk of developing OSCC, this may also occur in non-dysplastic lesions. However, no reliable markers exist to predict the occurrence of OSCC in these patients. From a total of 263 patients diagnosed with oral white patches, biopsies from 45 patients were selected on the criteria that the patients had lesions histologically proven to be non-dysplastic. The lesions were analyzed with respect to their DNA content. The clinical outcome of the patients was known from the Cancer Registry of Norway, and these data were compared to the DNA content of their lesions. Among the 45 patients, five cases (11%) later developed an OSCC. Four of the cases that subsequently developed an OSCC were among the five aneuploid (abnormal) cases (P=0.001). One aneuploid lesion did not develop a carcinoma during a follow-up time of 120 months. The fifth case that subsequently developed an OSCC was diploid (normal), and developed into an OSCC after an observation time of 73 months (P=0.001). In conclusion, aberrant DNA content reliably predicts the occurrence of OSCC in patients that otherwise would be regarded as at very low risk. Normal DNA content indicates low risk.

Adult↗
PubMed2003

P2X7 subunit-like immunoreactivity in the nucleus of visceral smooth muscle cells of the guinea pig.

P2X receptors are adenosine 5'-triphosphate (ATP)-gated cation-selective channels. Seven cloned subunits (P2X(1-7)) are found in the plasma membrane of many cells in the brain and periphery. ATP-dependent opening of nuclear membrane channels, which resemble P2X(7) receptors, has been reported previously. Therefore, the aim of this study was to use specific antisera to examine P2X(7) receptor subunit expression in the nucleus of cells in visceral organs. In sections of the guinea pig vas deferens and bladder, widespread nuclear immunoreactivity was observed in smooth muscle, epithelial, and lamina propria cells using two antisera raised against different sequences within the P2X(7) subunit. Nuclear immunostaining was also seen in a variety of cell types in the myocardium, lung, stomach, ileum, and colon of the guinea pig. In all tissues, omission of the primary antisera or preincubation of the primary antisera with the antigenic peptide resulted in the loss of specific immunostaining, as did dilution of the antisera beyond 1:32000 or omitting antigen retrieval. Western blot analysis revealed that the anti-P2X(7) antiserum recognised a protein in membrane preparations from both guinea pig vas deferens nuclei and HEK-293 cells transfected with P2X(7) subunits. Thus, the nuclear expression of P2X(7) receptors appears to be widespread in smooth muscle and epithelial cells of visceral organs.

Animals↗
PubMed2000

A new method of comprehensive static histomorphometry applied on human lumbar vertebral cancellous bone.

The aim of the present study was to assess age-related changes in the human spine by use of established static histomorphometry, and to determine how these static histomorphometric measures are interrelated in human cancellous bone tissue. The material comprised normal human lumbar vertebral bodies (L-2) from 12 women (19-96 years) and 12 men (23-91 years) selected from a larger autopsy material to give an even age and gender distribution. In addition, L-2 from three female subjects (80, 88, and 90 years) with a known vertebral fracture of L-2 were considered. Approximately 9-mm-thick frontal (mediolateral) slices were embedded in methylmetacrylate, stained with aniline blue, and scanned into a computer with a flatbed image scanner at a high resolution (2400 dpi). With a custom-made computer program the following static histomorphometric measures were determined: trabecular bone volume; marrow space star volume; bone space star volume; anisotropy of bone and marrow phase (star length distribution method); node-strut analysis (node:terminus ratio); trabecular thickness; trabecular number; trabecular separation; and trabecular bone pattern factor. In addition, connectivity density was determined (by the ConnEulor method). All 11 histomorphometric measures, except bone space star volume and the two measures of anisotropy, showed a significant correlation with age. Marrow space star volume (r = 0.82) and trabecular bone volume (r = -0.81) showed the highest correlation with age. Furthermore, it was found that all of the histomorphometric measures were correlated, to different degrees. Trabecular bone volume correlated significantly with all ten histomorphometric measures, whereas the two anisotropy measures were poorly correlated to the other measures. Finally, we found the histomorphometric values in this study to be in excellent accordance with various previously published results from studies of human trabecular vertebral bone, the sole exception being marrow space star volume, which was probably due to the small (artificial) region of interest (ROI) that was used in the earlier studies. In conclusion, the new method applied herein allows for easy assessment of age-related changes and also for assessment of relationships between histomorphometric measures in human vertebral cancellous bone.

Adolescent↗
PubMed2001

Mechanisms by which high-dose estrogen therapy produces anabolic skeletal effects in postmenopausal women: role of locally produced growth factors.

Conventional hormone replacement therapy acts primarily by preserving bone, but cannot restore lost bone in women with established osteoporosis. Studies in rodents have shown that high doses of estrogens have anabolic skeletal effects, and recent observations in a group of women treated long term with high doses of estrogen indicated that similar effects occur in humans. This study examines the hypothesis that locally produced growth factors, including transforming growth factor-beta (TGF-beta) and platelet-derived growth factors (PDGFs), are involved in mediating the anabolic effects of high-dose estrogen. Transiliac-crest bone biopsies were taken from ten women, aged 52-67 years (mean 58 years), who had been treated with high-dose estrogen for 15 years. Control samples were obtained from four age-matched postmenopausal women not receiving estrogen therapy. TGF-betas and PDGFs were analyzed for mRNA and protein expression by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. Results showed both TGF-beta1 and -beta2 mRNA, expressed as a ratio to GAPDH, were increased in the estrogen-treated group with an eightfold increase for TGF-beta1 (0.258 +/- 0.246 [mean +/- SD] vs. 0.032 +/- 0.053 in the control group, p = 0.02) and a twofold increase for TGF-beta2 (p = n.s.). TGF-beta3 analysis showed only negligible amounts in both groups. Protein expression levels for TGF-beta1, -beta2, -betaRI and -RII were higher in the estrogen-treated group than in controls, the most marked effects being seen for TGF-beta1. PDGF-A protein expression was also significantly higher in osteoblasts and osteocytes in women treated with estrogen, whereas PDGF-B showed only modest differences. The percentage of bone surface occupied by osteoclasts, as determined by tartrate-resistant acid phosphatase (TRAP) staining, was significantly reduced in the estrogen-treated group (p = 0.001). These results demonstrate that high-dose estrogen therapy is associated with increased TGF-beta, TGF-betaR, and PDGF synthesis and decreased osteoclast activity, consistent with the hypothesis that these growth factors may mediate the actions of estrogen in bone.

Acid Phosphatase↗
PubMed1999

Histomorphometric studies show that bone formation and bone mineral apposition rates are greater in C3H/HeJ (high-density) than C57BL/6J (low-density) mice during growth.

High-density C3H/HeJ (C3H) and low-density C57BL/6J (B6) mice, with femoral bone density differing by 50%, were chosen as a model to investigate the mechanisms controlling peak bone density and to map peak bone density genes. The present longitudinal study was undertaken to further establish the bone biologic phenotypes of these two inbred strains of mice. To evaluate phenotypic differences in bone formation parameters in C3H and B6 mice between the ages of 6 and 26 weeks, undecalcified ground sections from the diaphyses of the tibia and femur were prepared from mice receiving two injections of tetracycline. Histomorphometric analyses revealed that the cortical bone area was significantly greater (16%-56%, p < 0.001) in both the femur and tibia of the C3H mice than in the B6 mice at all timepoints. This difference in cortical bone area was due to significantly smaller medullary areas in the C3H mice than in the B6 mice. The bone formation rates (BFR) at the endosteum in both the femur and tibia were significantly greater (28%-117%,p < 0.001) in the young C3H mice (6-12 weeks old) than in B6 mice. The higher bone formation in C3H mice was associated with higher values of the bone mineral apposition rate (25%-94%, p < 0.001), and was not associated with higher values of the forming surface length as measured by tetracycline label length. Similar interstrain differences in mineral apposition and bone formation rates were observed in the periosteum of the femur and tibia. In conclusion, the greater bone area in the high-density C3H mice vs. the low-density B6 mice was, in part, due to the greater periosteal and endosteal bone formation rates during growth in the C3H mice. Because the C3H and B6 mice were maintained under identical environmental conditions (diet, lighting, etc.), the observed interstrain differences in bone parameters were the result of the action of genetic factors. Consequently, these two inbred strains of mice are suitable as a model to identify genetic factors responsible for high bone formation rates.

Animals↗
PubMed1999

Effects of age, estrogen depletion, and parathyroid hormone treatment on vertebral cancellous wall width in female rats.

The main goal of this study was to determine whether vertebral cancellous wall width changes with age and parathyroid hormone (PTH) treatment in rats. Female Sprague-Dawley rats were subjected to sham surgery or ovariectomy at 3 months of age. One month after surgery, ovariectomized (ovx) rats were injected subcutaneously (s.c.) 5 days/week for 6 weeks with vehicle or human parathyroid hormone [hPTH (1-34)] at a dose of 80 microg/kg body weight. Sham-operated control rats were injected s.c. with vehicle alone. All rats from this first study were 5.5 months of age at the time of killing. In the second study, control and ovx rats were subjected to the same treatments for a 10-week period beginning at one year after surgery. These animals were 17.5 months of age at the end of the study. The first lumbar vertebra was collected from each rat and processed undecalcified for measurements of cancellous wall width. At 5.5 months of age, control and ovx rats had nearly identical mean values for vertebral cancellous wall width, but this remodeling variable was significantly increased in PTH-treated ovx rats. At 17.5 months of age, wall width in control and ovx rats decreased significantly compared with wall width in the younger rats. PTH treatment of aged ovx rats induced a significant increase in vertebral cancellous wall width when compared with vehicle treatment of aged ovx rats. These results, which are consistent with findings in humans, indicate that vertebral cancellous wall width decreases with age in intact female rats and in ovx rats, but increases in ovx rats in response to PTH treatment. Furthermore, the results add to the growing body of evidence that substantial cancellous bone remodeling occurs in the vertebral bodies of rats.

Aging↗
PubMed1999

Missing observations in bone histomorphometry on osteoporosis: implications and suggestions for an approach.

Crucial bone histomorphometric indices, i.e., turnover-related indices, are based on tetracycline double labeling. However, these indices are particularly exposed to loss of information because of missing readings on double labels. If the failure to make the observation is related to its magnitude, then selection bias may invalidate the conclusions. Therefore, ignoring missing double labels may lead to a selection of high-turnover patients. The aim of this study was to analyze the dimension and the impact of excluding iliac crest bone biopsies with missing readings in women with spinal crush fracture osteoporosis (n = 158, median 68 years, range 49-80 years). Furthermore, two different lower limits of the mineral apposition rate (MAR) were examined to explore their usefulness as a biological minimum that can be used for cases with missing readings, i.e., recoding of missing values. The average MAR (calculated as the mean of all interlabel widths measured in each individual) shows a lower limit of 0.3 microm/day, suggesting an apparent minimum for the interlabel width (Ir.L.Wi) of 3-4 microm. Identifying the smallest interlabel width measured in each individual and calculating the minimal MAR shows that 77% of the minimal MAR values are below 0.3 microm/day and reach a minimum of 0.1 microm/day, corresponding to an interlabel width of about 1 microm. Therefore, the minimal MAR presents a biological minimum of 0.1 microm/day. This value is used for our recoding: if no labels are sampled (2% of our population), Ir.L.Wi is assigned the value 0; if none or an insufficient number of double labels are sampled (29% of our population), then Ir.L.Wi is assigned the value 1 microm. Excluding cases with missing readings on any dependent variable increases the mineralizing surface (MS/BS) by 60% (2p < 0.01); other indices show no significant change. The suggested recoding decreases the average MAR by 4% (2p < 0.01), prolongs the remodeling period by 19% (2p < 0.01), and tends to decrease the activation frequency (2p = 0.09). Furthermore, the number of excluded biopsies tends to be larger among the older (2p = 0.09) and more severely osteopenic individuals (2p = 0.09). We conclude that ignoring missing double labels leads to selection bias; therefore, specific measures such as recoding procedures are needed to allow proper representation of low turnover patients. There is also a risk of bias caused by the exclusion of the older, osteopenic patients in bone histomorphometric osteoporosis trials.

Aged↗
PubMed1999

Trypanosoma brucei spp. development in the tsetse fly: characterization of the post-mesocyclic stages in the foregut and proboscis.

Post-mesocyclic development of Trypanosoma brucei in the tsetse fly in its migration from midgut to salivary glands, was revisited by sequential microdissection, morphometry and DNA-cytofluorometry. This development started by day 6 after the infective feed, with passage of mesocyclic midgut trypomastigotes through proventriculus and upward migration along foregut and proboscis to the salivary gland ducts. Kinetics of salivary gland infection showed that colonization of the salivary glands by epimastigotes occurred only during the time-limited presence of this developmental phase in the foregut and proboscis. Post-mesocyclic trypanosomes in the foregut and proboscis were pleomorphic, with 4 morphological stages in various constant proportions and present all through from proventriculus up to the salivary gland ducts: 67% long trypomastigotes, 27% long epimastigotes, 4% long epimastigotes undergoing asymmetric cell division and 2% short epimastigotes. Measurements of DNA content demonstrated a predominant tetraploidy for 67% of these trypanosomes, the remainder consisting of the homogeneous diploid short epimastigotes and some long epimastigotes. According to the experimental data, the following sequence of trypanosome differentiation in the foregut and proboscis is proposed as the most obvious hypothesis. Incoming mesocyclic trypomastigotes (2N) from the ectoperitrophic anterior midgut start to replicate DNA to a 4N level, are arrested at this point, and differentiate into the long epimastigote (4N) which give rise, by an asymmetric cell division, to 2 unequal, diploid daughter cells: a long, probably dead-end long epimastigote and a short epimastigote. The latter is responsible for the epimastigote colonization of the salivary glands if launched at the vicinity of the gland epithelium by the asymmetric dividing epimastigote.

Animals↗
PubMed1997

Ploidy level determination and quantitative chromatin pattern description in pregnancy-associated breast cancers.

The present study deals with the characterization of hormone-sensitivity in pregnancy-associated breast cancers (PBCs). This characterization was carried out in 22 PBCs as opposed to 88 non-pregnancy-associated breast cancers (NPBCs). For this study, we used the digital cell image analysis of Feulgen-stained nuclei to assess the type of hormone-sensitivity. In a previous study it was demonstrated that the chromatin pattern in breast cancers is related to the amounts of estrogen receptors they contain. Our results demonstrated that the quantitative description of the chromatin pattern by means of 15 parameters (relating to morphometric, densitometric, and textural features) made it possible to identify typical cell nuclei populations in the PBC and NPBC groups. The use of specific statistical analyses (principal-components and discriminant) made it possible to quantify the proportion of each cell nucleus type in the PBCs. Furthermore, of the 22 PBCs under study, 13 contained a large majority of cell nuclei whose chromatin pattern was characteristic of hormone-sensitive cells, while 5 cases contained a large majority of typically hormone-insensitive ones. The remaining 4 cases contained a relatively similar proportion of typically hormone-sensitive and insensitive cell nuclei. The quantitative chromatin pattern description thus made it possible to characterize the hormone-sensitivity level in PBCs, whereas DNA ploidy level determination did not enable any such characterization to be carried out. The chromatin pattern assay described here, which enables hormone-sensitive pregnancy-associated breast cancers to be identified from hormone-insensitive ones independently from biochemical assays, should help the physician regarding therapy adaptation.

Breast Neoplasms↗
PubMed1997

Histopathology grading in small breast cancers < or = 10 mm--results from an area with mammography screening.

Histopathological malignancy grading using the Bloom-Richardson classification of ductal cancers was performed for 248 invasive ductal breast cancers < or = 10 mm operated 1978-1985. There were significantly more grade 1 lesions in the prevalence screening round. Grade 3 was correlated with aneuploidy, higher S-phase (SPF), and more receptor negative tumours. There were also significantly more positive lymph nodes in grade 3 lesions, 18% compared to 5% and 12% respectively for grades 1 and 2 (p < 0.05). In life table analysis for survival, when the high risk group of grade 3 lesions was compared to the grade 1 and 2 lesions combined, five-year disease-free survival was 84.6% vs. 99.1% (p < 0.001). With good training and care from the pathologist, malignancy grading seems useful for prognostication of eventual recurrence and death. In tumours 10 mm or smaller only grade 3 lesions need to be included in follow-up systems and should probably have adjuvant treatment. Malignancy grading is especially good in small ductal breast cancers where grading can always be performed while other prognostic determinations are hampered by shortage of material. Lymph node positivity is also low in this group.

Adult↗
PubMed2001

An oscillating extracellular voltage gradient reduces the density and influences the orientation of astrocytes in injured mammalian spinal cord.

We have studied the cellular basis for recovery from acute spinal cord injury induced by applied electric fields. We have emphasized this recovery is due to the regeneration of spinal axons around and through the lesion, and have begun to evaluate the contribution of other cells to the recovery process. We have imposed a voltage gradient of about 320 microV/mm across puncture wounds to the adult rat spinal cord in order to study the accumulation and orientation of GFAP+ astrocytes within and adjacent to the lesion. This electric field was imposed by a miniaturized electronic implant designed to alternate the polarity of the field every 15 minutes. Astrocytes are known to undergo hyperplastic transformation within injured mammalian cords forming a major component of the scar that forms in response to injury. We have made three observations using a new computer based morphometry technique: First, we note a slight shift in the orientation of astrocytes parallel to the long axis of the spinal cord towards an imaginary reference perpendicular to this axis by approximately 10 degrees--but only in undamaged white matter near the lesion. Second, the relative number of astrocytes was markedly, and statistically significantly, reduced within electrically--treated spinal cords, particularly in the lesion. Third, the imposed voltage gradient statistically reduced the numbers of astrocytes possessing oriented cell processes within the injury site compared to adjacent undamaged regions of spinal cord.

Animals↗
PubMed2001

Structure of renal glomeruli in hypertensive NISAG rats reared by normotensive females.

Morphometry of ultrastructural components of renal glomeruli in 3-week- and 6-month-old rats with hereditary stress-induced arterial hypertension (NISAG rats) reared by normotensive Wistar females showed deceleration of the development of arterial hypertension in NISAG rats and attenuated its negative consequences for kidneys as the target organs.

Animals↗
PubMed2001

DNA endoreplication in the clustered supramedullary neurons of the pufferfish Diodon holacanthus L. (osteichthyes).

DNA contents, ranging from 4C to more than 500C, were determined by a quantitative microfluorimetric assay in supramedullary neuron nuclei of the pufferfish Diodon holacanthus. The distribution of C values after ethidium bromide staining indicates an inter- and intra-individual variation in DNA contents which do not correspond to duplications of the total genome, suggesting that DNA replication is specific for particular genes (endoreplication). Moreover, the DNA content appears to be correlated with nuclear size. A relationship between the DNA amounts and the presence of AT- and GC-rich sequences has been shown. This work demonstrates, for the first time, DNA endoreplication in a specific neuronal type in vertebrates.

Animals↗
PubMed2004

Inverse correlation between genetic aberrations and malignancy grade in ependymal tumors: a paradox?

OBJECTIVE: The goal of our study was to investigate the inverse correlation between number of genetic aberrations and malignancy grade in ependymal tumors at the ploidy level. METHODS: we examined seven myxopapillary ependymomas (mpEs) (WHO grade I), 28 spinal and cerebral ependymomas (Es) (WHO grade II), and 18 cerebral anaplastic ependymomas (aEs) (WHO grade III) using image DNA cytometry. The ploidy status was correlated with clinicopathological characteristics and with the results obtained by comparative genomic hybridization (CGH) analysis that we performed in about half of these tumors. RESULTS: mpEs were exclusively located in the spinal cord and aEs in the cerebrum only, whereas Es were located in both the spinal cord and brain. We found aneuploidy or tetraploidy to be common in the group of mpEs (6 out of 7) and much less frequent in Es (6 out of 28) and aEs (4 out of 18). Three-year postoperative survival was 100% for mpEs, 100% for spinal Es, 92% for cerebral Es, and 33% for aEs. Our CGH results in a selection of these tumors revealed the highest number of genetic aberrations in the mpEs (average 16; n = 2), a lower number in Es (average 12; n = 11) and the lowest number in aEs (average 5; n = 6). Interestingly, in the group of Es and aEs, a high number of genetic aberrations as detected by CGH was not correlated with aneuploidy or tetraploidy. Three patients, all with mpEs had local seeding. CONCLUSION: These results underline that mpEs are distinctly different from Es and aEs at the genetic level and that extensive genomic alterations and aneuploidy in ependymal tumors are not in itself an indicator of malignant behavior.

Adolescent↗
PubMed2004

Tri-dimensional morphometric analysis of astrocytic processes with high voltage electron microscopy of thick Golgi preparations.

A characteristic feature of the astrocytic processes is to assume the form of shin sheets or lamellate coverings of other brain constituents. We analyzed the extensive and finely divided processes of the protoplasmic astrocyte in the molecular layer of the rat dentate gyrus by means of computer electron tomography and stereo-photogrammetry using tilted high voltage electron microscope images of thick Golgi preparations. The surface area and volume of the astrocytic processes were measured and the surface/volume ratios were estimated. The surface/volume ratios of astrocytic processes in the neuropile ranged from 18.9 to 33.0 per microm, and the mean value was 26.2+/-5.0 per microm. The values were roughly comparable to those previously reported for the microdomain of Bergmann glia cell terminal processes in the rat cerebellum, which were estimated from reconstructions using thin serial section electron microscope images. The large surface to volume ratio of the astrocytic processes in the neuropile resulted from the lamellar nature of the processes interposed between other cellular elements, and may reflect the functional activities of the astrocyte. The results suggest the usefulness of the electron tomography and stereo-photogrammetry for three-dimensional morphometrical analysis of the astrocytic processes, although both techniques can be expected to be refined further in order to provide more precise measurements of these complicated processes.

Animals↗
PubMed2000

Inverse correlation between Ink4-locus deletions and ICM-DNA hyperdiploidy in childhood acute lymphoblastic leukaemia, relation to clinical characteristics and outcome.

Malignant cells from 72 children with ALL were analysed to investigate the relationship between DNA-ploidy and deletion of the Ink4 locus containing the cell-cycle regulating genes p16ink4a, p15ink4b and p14ARF. Image-DNA cytometry (ICM) was used to assess DNA index (DI), and Southern hybridisation was carried out to detect deletions of the Ink4-locus in the leukaemic cells. A DNA content equal to or exceeding 1.16, indicating hyperdiploidy, was detected in 21/72 patients (29%), 1/72 (1.3%) showed DNA-hypodiploidy, and the remaining 50 patients (69%) had a DI within normal limits. Bi-allelic deletion of at least two of the coding sequences from the Ink4 locus was observed in 23/70 (33%) patients. Mono-allelic deletions within the locus were observed in 10/70 patients (14%), and 37/70 patients (53%) had normal signals for both sequences. Out of the 70 patients that could be analysed by both techniques only two had the combination of DNA hyperdiploidy and Ink4-locus bi-allelic deletion (p = 0.004). DNA hyperdiploidy was not associated with any specific clinical characteristics, but there was a trend for a better prognosis for patients with DNA hyperdiploidy (p = 0.09). Ink4-locus deletion was associated with T-cell phenotype and higher white blood cell counts at diagnosis and poor prognosis (p = 0.0015). Multivariate analysis confirmed that Ink4-locus deletion is an independent prognostic marker and a stronger determinant of outcome than DNA ploidy. When DNA ploidy and Ink4-locus deletions were combined, novel subgroups with significantly different outcome could be observed. A group with DNA index > or = 1.16 and no Ink4-locus bi-allelic deletions had an excellent prognosis (p-EFS 0.93 at 60 months), patients with Ink4-locus bi-allelic deletion and a DNA index < 1.16 fared worst (p-EFS 0.57) and patients with no Ink4 deletions and without hyperdiploidy had an intermediate outcome (p-EFS 0.79). The reason for the inverse correlation between DNA ploidy and Ink4 deletion and their combined impact on prognosis remains unclear, and possible reasons are discussed.

Actuarial Analysis↗