A phase II trial with rosiglitazone in liposarcoma patients

Agents of the thiazolidinedione drug family can terminally differentiate human liposarcoma cells in vitro by activating genes responsible for lipocyte differentiation. One study has shown clinical activity of troglitazone treatment in liposarcoma patients. We sought to find further evidence for this result. In all, 12 patients with a liposarcoma received rosiglitazone 4 mg b.d. They were followed clinically and with repeated biopsies for histological and biological studies. At the molecular level the mRNA translation of three genes that are induced by this treatment (peroxisome proliferator-activated receptor γ (PPARγ), adipsin and fatty acid binding protein) was determined. Nine patients were eligible for evaluation. One patient had to stop treatment due to hepatotoxicity. The mean time to progression was 6 months (2 – 16 months), with one patient still on treatment. We did not see any significant change in histologic appearance of the liposarcomas by the treatment. The level of gene expression changed significantly in two patients, but this did not result in a clinical response. Based on this study, rosiglitazone is not effective as an antitumoral drug in the treatment of liposarcomas. Increased PPARγ activity does not correlate with the clinical evolution.

12p-Amplicon structure analysis in testicular germ cell tumors of adolescents and adults by array CGH

All invasive testicular germ cell tumors of adolescents and adults (TGCTs), that is, seminomas and nonseminomas, show gain of 12p sequences, mostly as isochromosomes. Although several candidate genes have been suggested, the relevant gene(s) have not been identified yet. About 10% of testicular seminomas, however, show a more restricted amplification of the 12p11.2-p12.1 region, in which the various amplicons show an apparent overlap, allowing for the shortest region of amplification overlap approach, aiming at the identification of pathogenetically relevant sequences residing in this region. Here we report on a high-resolution 12p-amplicon architecture analysis using microarray-based comparative genomic hybridization, the results of which were subsequently confirmed by fluorescent in situ hybridization studies. The 12p-specific microarray contained 63 positionally selected BAC clones, which are more or less evenly distributed over the short arm of chromosome 12 (average spacing: less than 500 Kb), including 20 clones within the region of amplification. Out of a series of 17 seminomas, seven seminomas showed amplification of the whole amplicon region, of which three showed a dip in T/R value in the center of the amplified area. A more complex amplification pattern was found in the other 10 seminomas: three showed predominant amplification at the centromeric border; one mainly at the telomeric border; six showed a balanced amplification of both the centromeric and telomeric regions. The only nonseminoma investigated showed a structure in which the centromeric border was only amplified. These data support a mechanistic model in which at least two 12p genes, situated at the border regions of the amplicon, are positional candidates capable of actively supporting tumor progression in TGCTs.

Endometrial stromal sarcoma presenting as postpartum haemorrhage: report of a case with a sole t(10;17)(q22;p13) translocation

BACKGROUND

Although the clinical picture of endometrial stromal sarcoma (ESS) is variable, it was never reported to present as a postpartum hemorrhage. In addition, ESS is a tumor type of which, due to its rarity, little is known regarding chemosensitivity and genetic changes.

CASE

A 28-year-old woman complaining of persistent postpartum bleeding was referred to our hospital, where she was diagnosed with ESS. At laparotomy, the invasion of nervous and vascular pelvic structures rendered her inoperable, and chemotherapy (doxorubicin 50 mg/m(2) for 15 min; ifosfamide 5 g/m(2)/24 h; mesna 5 g/m(2), every 3 weeks) was initiated. The ESS appeared to be chemosensitive because after three treatment cycles the tumor iliac metastase significantly decreased in volume and became surgically removable. Chemosensitivity was confirmed microscopically. Three additional courses of chemotherapy and pelvic irradiation were administered. Cytogenetic evaluation of both the primary as well as the metastatic lesions revealed a t(10;17)(q22;p13) as the sole cytogenetic abnormality.

CONCLUSIONS

Three interesting features of this particular case put ESS in a new perspective. First, the fundal ESS permitted normal conception and pregnancy but caused a postpartum haemorrhage. Second, the ESS was clearly chemosensitive. Third, we report a novel cytogenetic aberration in ESS, the molecular characterization of which might lead to the identification of the deregulated pathway(s) triggering tumor development in ESS.

ALK-ATIC fusion in urinary bladder inflammatory myofibroblastic tumor

In this report, we describe an inflammatory myofibroblastic tumor (IMT) of the urinary bladder in a 46-year-old man. Tumor cells presented striking cytoplasmatic ALK immunopositivity. Cytogenetic and FISH analysis, by use of a multicolor chromosome 2 banding probe, revealed a 46,XY,der(2)(2pter-->2p23:2q35-->2q37:2p11-->2q35:2p23-->2p11:2q37-->2qter) karyotype. Subsequent FISH and RT-PCR analysis confirmed the ALK-ATIC chimeric fusion in tumor cells. This is the first evidence of a variant rearrangement involving the ATIC gene in IMT and the first cytogenetic description of an IMT originating from the urinary bladder.

Complex genomic rearrangement of ALK loci associated with integrated human Epstein-Barr virus in a post-transplant myogenic liver tumor

Epstein-Barr virus (EBV) is a ubiquitous viral agent, well known to be associated with lymphoid, epithelial, and smooth-muscle malignancies in immunocompromised individuals. This report describes a 10-year-old patient with an EBV-related liver tumor occurring after kidney transplantation. The neoplasm presented a phenotypic spectrum, ranging from a smooth-muscle tumor to an inflammatory pseudotumor (IPT). The neoplastic cells failed to disclose CD21, CD35, or ALK expression, the latter confirmed by reverse-transcription polymerase chain reaction. Cytogenetic analysis revealed a single clonal cell population showing 46,XY,del (2)(p23),der(3)t (2;3)(p23;q29),der(21) t(Y;21)(q12;p13) karyotype. By metaphase FISH analysis, the neoplastic cells demonstrated the presence of two molecularly different but related aberrant clones, one with the loss of one ALK allele and the second with translocation of the 3'end of ALK kinase domain on the der(3) chromosome. Using FISH with an EBV-specific and 3'end ALK DNA probes, a co-localization of the viral DNA and the ALK sequences was found on the der(3) chromosome. Metaphases with loss of rearranged ALK did not show integrated virus; instead, viral particles together with an associated 3'end ALK domain formed an ex-chromosomal, episomal-like type configuration. The interphase study, using dual-color 5'/3' end ALK FISH assay, revealed 30% of nuclei with only one fused signal, confirming the total loss of one ALK allele in the subset of tumor cells. A combined immunofluorescence and FISH study indicated this separate clonal variant to correspond to desmin-positive smooth-muscle cells. In contrast, desmin-negative myofibroblasts showed the presence of both normal and rearranged ALK alleles. Our results indicate that ALK locus may be a target of EBV integration, a hitherto unreported finding. Although the sustained clonal expansion in EBV-related smooth-muscle tumors/IPTs may depend on functions provided by the EBV oncogenic proteins, the tumor phenotype may be further modified by the secondary genomic rearrangements imposed by the virus during and/or after the integration event. In this respect, the observed phenotypic heterogeneity most likely reflects divergence during neoplastic progression, with the subsequent expansion of morphologically and molecularly distinct but cytogenetically related clones.

Cytogenetic comparison between clear cell sarcoma and a case of acral clear cell melanoma

BACKGROUND

Clear cell melanoma is a recently described variant of melanoma characterized by prominent clear cell features similar to clear cell sarcoma.

PATIENTS AND METHODS

The present report describes a deeply invasive case of clear cell melanoma clinically, histologically, immunohistochemically, ultrastructurally and with the FISH technique and compares these findings with those in clear cell sarcoma.

RESULTS

A 68-year-old male presented with an ulcerated, deeply invasive melanoma on the heel, corresponding to Clark level V, with a maximum tumour thickness of more than 14 mm; follow-up revealed inguinal lymph-node and lung metastases. Apart from characteristic histological features of melanoma with intraepidermal involvement, the lesion was immunohistochemically positive for 5100 protein, with HMB45 and A103 (anti-human Melan-A/MART-1), and ultrastructurally showed melanosomes. In deeply invasive parts, the lesion was indistinguishable from clear cell sarcoma, exhibiting nests, fascicles and sheets of pale-staining epithelioid to spindle-shaped cells ('clear cells') with scattered Touton-like multinucleated giant cells. Cytogenetic analysis using the FISH technique revealed a 12q13 chromosomal break in the vicinity of the ATFI gene but without ATF1 disruption.

CONCLUSION

These findings may indicate the possible involvement of the ATF1 gene in clear cell melanoma tumorigenesis, similar to clear cell sarcoma with classical t(12;22) translocation.

Lipoblastoma in a 23-year-old male: distinction from atypical lipomatous tumor using cytogenetic and fluorescence in-situ hybridization analysis

Lipoblastoma is a rare benign tumor that occurs primarily in infancy and early childhood. We present the rare presentation of a 12 cm sized intramuscular lipoblastoma of the thigh in a 23-year-old patient. On histology, the tumor strongly resembled an atypical lipomatous tumor due to the presence of lipoblasts and atypical stromal nuclei. The very focal lobulation and myxoid change presented the only histological hint towards a lipoblastoma. Cytogenetic and subsequent FISH evaluation of the tumor cells showed a 46,XY, t(8;15) (q12;q25) as chromosomal change with rearrangement of the PLAG1 gene. The present case indicates that lipoblastoma should enter the differential diagnosis of an 'atypical' deep seated fatty tumor in adults. The diagnostic value of cytogenetic/molecular analysis in the differential diagnosis of lipomatous tumors is underscored as well.

Endometrial stromal sarcoma with a sole t(X;17) chromosome change: report of a case and review of the literature

BACKGROUND

Endometrial stromal sarcomas (ESSs) exhibit varying degrees of malignancy and heterogeneity at the karyotypic level. The biological mechanisms that contribute to tumorigenesis of ESS are still largely unknown.

CASE

A 33-year-old woman suffering from ESS was treated primarily surgically. Cytogenetic evaluation of the primary uterine nodule and metastatic tumor showed 46,XX,t(X;17)(p11:q23) karyotype in all metaphases analyzed. Normal endometrial cells exhibited 46,XX karyotype. Fluorescence in situ hybridization analysis confirmed the presence of the reciprocal t(X;17) translocation and allowed for the positioning of the chromosome X breakpoint distal to SSX1 gene loci.

CONCLUSIONS

Our report of a previously undescribed sole cytogenetic translocation in an advanced stage of ESS might identify a cytogenetically distinct subgroup of ESS and help to reveal genes involved in ESS tumorigenesis.

Primitive neuroectodermal tumor in the cerebellopontine angle with isochromosome 17q presenting as meningioma in a woman 26 years of age

An unusual posterior fossa neoplasm in a 26-year-old woman with short history of the cerebellar symptoms is presented. CT and MR images showed the tumor within the cerebellopontine angle, suspected as meningioma. At surgery, the tumor was dura-attached and did not infiltrate the arachnoid. Histologically, the neoplasm was a small blue cell tumor with solid and microcystic pattern, consistent with primitive neuroectodermal tumor (PNET). Immunohistochemically the cells were strongly positive for NCAM and GFAP. Fluorescence in situ hybridization (FISH) was performed with the cosmids G9 and F7 (flanking EWSR1/22q12 region) DNA probes and dual-color spectrum-orange LSI HER-2/neu (17q11.2)/spectrum green CEP17 (17p11.1-q11.1) DNA probe. The presence of isochromosome 17q within neoplastic cells was found. The tumor was classified as a medulloblastoma. We demonstrate the utility of a multidisciplinary approach to nervous system tumor diagnosis. The clinical features together with histological, immunohistochemical, and characteristic molecular alteration allowed classification of the presented case.

Clustering of deletions on chromosome 13 in benign and low-malignant lipomatous tumors

Deletions and structural rearrangements of the long arm of chromosome 13 are frequently observed in benign and low-malignant lipomatous tumors, but nothing is known about their molecular genetic consequences. We assessed the karyotypes of 40 new and 22 previously published cases (35 ordinary lipomas, 15 spindle cell/pleomorphic lipomas, 2 myxolipomas, 1 angiomyxolipoma and 9 atypical lipomatous tumors) with chromosome 13-abnormalities, and found bands 13q12-22 to be frequently affected. Twenty-seven cases with structural abnormalities within this region were selected for breakpoint and deletion mapping by metaphase fluorescence in situ hybridization (FISH), using a set of 20 probes. Deletions were found in 23 of 27 cases. The remaining 4 cases had seemingly balanced rearrangements. The breakpoints were scattered but clustered to band 13q14, and in all cases with unbalanced abnormalities, a limited region within band 13q14 was partially or completely deleted. A deletion within band 13q14 was found together with a breakpoint on the other homologue in 5 cases, 4 of which could be tested further with regard to the status of the retinoblastoma (RB1)-gene. In all 4 cases, only 1 copy of the gene was deleted. In addition to the breaks and deletions in the vicinity of the RB1-locus, several other regions of 13q were recurrently affected, e.g., in the vicinity of the hereditary breast cancer (BRCA2; 13q12)- and lipoma HMGIC fusion partner (LHFP; 13q13)- genes. Our findings strongly indicate that deletion of a limited region (approximately 2.5 Mbp) within 13q14, distal to the RB1-locus, is of importance in the development of a subset of lipomatous tumors.

A unique occurrence of a cerebral atypical teratoid/rhabdoid tumor in an infant and a spinal canal primitive neuroectodermal tumor in her father

This report describes the clinical, pathological, immunohistochemical and genetic data of two rare malignant neoplasms of the central nervous system (CNS)--a cerebral atypical teratoid/rhabdoid tumor (AT/RT) in a 5-month-old girl and a spinal canal primitive neuroectodermal tumor (PNET) in her father. Despite aggressive treatment, both tumors were fatal, displaying extensive local recurrence and diffuse neoplastic dissemination. The paraffin-embedded tumor tissue samples were analyzed using a dual-color FISH with a locus specific LSI22q (BCR) probe. In the AT/RT tissue, a loss of BCR locus was observed in a significant proportion of the cells in contrast to the PNET specimen where the majority of nuclei did not reveal any loss of the BCR region. No mutations in exon 5 and no changes in SNP of intron 5 of hSNF/INI1 gene were found. In addition, analysis of loss of heterozygosity (LOH) was performed using a panel of 15 microsatellite markers of chromosome 22. No LOH were found in both tumor tissues. In both cases no constitutional mutations of gene TP53 were found. Analysis of the TP53 mutations in the tumor tissues revealed that the PNET, not the AT/RT tumor, was homozygous for a missense mutation at codon 175 (CGC ==> CAC). Thus, our findings emphasize the genetic differences between the two specimens and suggest that the occurrence of these two aggressive tumors of CNS in one family could be coincidental.

Loss of chromosome 22 and proliferative potential in ependymomas

Fluorescence in situ hybridisation (FISH) analysis using total chromosome 22 painting and locus specific 22q11.2 (bcr locus) probes was performed on sections from archival paraffin-embedded tumours obtained from 28 patients diagnosed with either ependymoma, WHO grade 11 (18 cases) or anaplastic ependymoma, WHO grade 111 (10 cases). The Ki-67 labelling index (LI) analysis was carried out in parallel to estimate the tumours' proliferative potential. Loss of chromosome 22 was revealed in eleven (39%) ependymomas, seven (39%) WHO grade II and four (40%) anaplastic variants. Concurrent cytogenetic analysis was performed on 11 tumours to confirm the loss of chromosome 22 in four cases; clones with a loss of chromosome 22, which was identified by FISH, were not detected by standard cytogenetics in two samples. The loss of chromosome 22 was restricted either to the tumours' site or to sex or age of the patients studied. The Ki-67 LI ranged from 0.1 to 32.0% (mean 4.3%). Low-grade tumours significantly showed a lower mean Ki-67 LI than those classified as anaplastic tumours (3.1% and 6.4%, respectively). Additionally, the mean Ki-67 LI for ependymomas with a loss of chromosome 22 was significantly lower than that for tumours with chromosome 22 disomy (1.6% and 6.0%, respectively, p = 0.05), indicating that loss of chromosome 22 may be associated with the subset of ependymomas characterised by low proliferative capacities.

Spindle-cell rhabdomyosarcoma with 2q36 approximately q37 involvement

The cytogenetic analysis of a spindle-cell variant of embryonal rhabdomyosarcoma (RMS), presenting as a cheek mass in an 18-year-old girl, is reported. The tumor cells showed an abnormal karyotype 46,XX,der(2)t(2;7)(q36 approximately q37;q3?),del(14)(q24),der(16)t(1;16)(q21;q13), with a tetraploid range of chromosome number in a subpopulation of cells. By fluorescence in situ hybridization analysis, the tumor cells were negative for FKHR-disrupting translocations specific for alveolar type of RMS and for NMYC gene amplification.

Role of gain of 12p in germ cell tumour development

Within the human testis, three entities of germ cell tumours are distinguished: the teratomas and yolk sac tumors of newborn and infants, the seminomas and nonseminomas of adolescents and young adults, referred to as testicular germ cell tumours (TGCT), and the spermatocytic seminomas. Characteristic chromosomal anomalies have been reported for each group, supporting their distinct pathogenesis. TGCT are the most common cancer in young adult men. The initiating pathogenetic event of these tumours occurs during embryonal development, affecting a primordial germ cell or gonocyte. Despite this intra-uterine initiation, the tumour will only be clinically manifest after puberty, with carcinoma in situ (IS) as the precursor. All invasive TGCT, both seminomas and nonseminomas, as well as CIS cells are aneuploid. The only consistent (structural) chromosomal abnormalities in invasive TGCT are gains of the short arm of chromosome 12, mostly due to isochromosome (i(12p)) formation. This suggests that an increase in copy number of a gene(s) on 12p is associated with the development of a clinically manifest TGCT. Despite the numerous (positional) candidate gene approaches that have been undertaken thus far, identification of a causative gene(s) has been hampered by the fact that most 12p gains involve rather large genomic intervals, containing unmanageable numbers of candidate genes. Several years ago, we initiated a search for 12p candidate genes using TGCT with a restricted 12p-amplification, cytogenetically identified as 12p11.2-p12.1. This approach is mainly based on identification of candidate genes mapped within the shortest region of overlap of amplification (SROA). In this review, data will be presented, which support the model that gain of 12p-sequences is associated with suppression of apoptosis and Sertoli cell-independence of CIS cells. So far, DAD-R is one of the most likely candidate genes involved in this process, possibly via N-glycosylation. Preliminary results on high through-put DNA- and cDNA array analyses of 12p-sequences will be presented.

PRCC-TFE3 renal carcinomas: morphologic, immunohistochemical, ultrastructural, and molecular analysis of an entity associated with the t(X;1)(p11.2;q21)

The reappraisal of genetically defined subsets of renal tumors can help to highlight the key pathologic features of specific neoplastic entities. We report the morphologic, immunophenotypic, ultrastructural, and molecular features of 11 renal carcinomas bearing a t(X;1)(p11.2;q21) and/or the resulting PRCC-TFE3 gene fusion. The male/female ratio was 4:7. Ten patients were in the age range of 9-29 years and one was 64 years old (mean 21.3 years, median 15 years). The predominant histologic pattern was nested, with islands of tumor cells compartmentalized by thin-walled capillary vasculature. Minor variations on this pattern yielded solid, acinar, alveolar, and tubular architecture. Papillary architecture was seen in nine cases, usually as a minor component. Neoplastic cells were typically characterized by irregularly shaped nuclei with vesicular chromatin and small nucleoli not visible with a 10x objective, and cytoplasm that ranged from clear to densely granular and eosinophilic. Mitoses were extremely rare; 5 were found in 900 high power fields examined from the 11 neoplasms. The most distinctive immunohistochemical feature of these neoplasms was moderate to intense nuclear labeling for TFE3 protein. These tumors were also consistently immunoreactive for the RCC antigen (10 of 11) and CD10 (9 of 9), whereas cytokeratin and epithelial membrane antigen were negative in four cases and were positive focally in the others. Ultrastructurally, all of the six neoplasms examined showed features consistent with conventional-type (clear cell) renal carcinoma, although two demonstrated distinctive intracisternal microtubules. Both tumors tested contained PRCC-TFE3 fusion transcripts. The differential diagnosis includes conventional-type papillary renal cell carcinoma, conventional-type (clear cell) renal carcinoma, and the ASPL-TFE3 renal carcinomas associated with the t(X;17)(p11.2;q25), with the latter two being morphologically the most similar to the t(X;1) renal carcinomas. Aside from their distinctive clinicopathologic features described here, there is experimental evidence suggesting that these tumors may show differential sensitivity to certain chemotherapeutic agents.

Clear cell sarcoma of the stomach

AIM

Clear cell sarcoma is a high-grade sarcoma with morphological features resembling malignant melanoma. This tumour is reported to display a characteristic distribution pattern nearly always involving the extremities. We report the first case of clear cell sarcoma of the stomach.

METHODS AND RESULTS

A 30-year-old male developed a huge tumour of the stomach, which at first glance could be considered as a poorly differentiated carcinoma. Immunohistochemical and ultrastructural examinations were consistent with a diagnosis of metastatic melanoma. However, cytogenetic examination revealed a t(12;22) translocation, specific for clear cell sarcoma. This was confirmed by fluorescence in-situ hybridization.

CONCLUSION

Making a reliable diagnosis of clear cell sarcoma of the stomach requires cytogenetic or molecular diagnostic investigations, particularly to rule out metastatic melanoma. This diagnosis avoids an unnecessary search for a primary melanoma.

Molecular cytogenetic mapping of recurrent chromosomal breakpoints in tenosynovial giant cell tumors

Tenosynovial giant cell tumor (TGCT) is the most common benign tumor of synovium and tendon sheath. Cytogenetic data indicate that 1p11-13 is the region most frequently involved in structural rearrangements. With the aim of eventually identifying the genes associated with TGCT development, we have investigated 1p11-13 breakpoints using fluorescence in situ hybridization (FISH) analysis, with a panel of yeast artificial chromosome (YAC) probes covering 1p11-21. Twenty-six tumors were analyzed by G-banding, and 24 of these showed a breakpoint in 1p11-13. The cytogenetic findings add to previous observations that, among a variety of translocations involving 1p11-13, chromosome 2 is the most common translocation partner, with a breakpoint in 2q35-37. This aberration was found in eight cases. Other recurrent translocation partners, found in two or three cases, were 5q22-31, 11q11-12, and 8q21-22. Material from 21 tumors was available for FISH analysis, which revealed that the breakpoints clustered to one region spanned by two YAC probes, 914F6 and 885F12 located in 1p13.2, in 18 cases. Bacterial artificial chromosome probes were used to map the recurrent breakpoint on chromosome 2. In four of seven cases there was a breakpoint within the sequence covered by probe 260J21, where the RDC1 gene is located, a gene reported to fuse with HMGIC in lipomas with a 2;12 translocation.

Correlation of the genotypes for N-acetyltransferases 1 and 2 with double bladder and prostate cancers in a case-comparison study

BACKGROUND

The arylamine N-acetyltransferases play a major role in the metabolic activation of carcinogenic amines that are present in cigarette smoke and a variety of other exogenous sources. The objective of this study was to determine the association of rapid or slow arylamine N-acetyltransferase (NAT) genotypes with smoking history and the risk for developing both bladder and prostate cancer.

PATIENTS AND METHODS

The subjects analyzed were a case group of 17 double-cancer patients and 34 age-matched controls who had benign prostatic hypertrophy, but were asymptomatic for prostate or bladder cancers. Genotyping of NAT1 and NAT2 alleles was done by restriction fragment length polymorphism and/or sequencing of NAT genes amplified from genomic DNAs by the polymerase chain reaction (PCR).

RESULTS

No significant correlation was found between NAT1 genotypes, double cancer, and smoking history. While NAT2-smoking interaction gave an odds ratio of only 1.70 (p = 0.117), a disproportionate number of cancer cases were genotypically rapid: 12 of 17 cancer cases vs. 13 of 34 controls (odds ratio 3.88; p = 0.040).

CONCLUSION

Rapid NAT2 genotype correlated significantly with the development of double prostate-bladder cancer.

Atypical lipomatous tumor in a 14-year-old patient: distinction from lipoblastoma using FISH analysis

Liposarcomas are rare in young age. We present the rare case of an atypical lipomatous tumor (synonym: well-differentiated lipoma-like liposarcoma) in a 14-year-old girl with the differential diagnosis of lipoblastoma which was excluded by fluorescence in situ hybridization (FISH) analysis. The tumor presented as a soft tissue mass at the dorsal part of the right thigh measuring up to 18 cm. Microscopically the lesion consisted of atypical adipocytes with hyperchromatic nuclei and additional multivacuolated lipoblasts. Interphase dual-color FISH performed with chromosome 8 centromeric and YAC164H5 (mapping to exons 2-5 of the PLAG1 gene) probes revealed no rearrangement of PLAG1 oncogene or polysomy of chromosome 8. Additional FISH using an MDM2 gene probe and an BAC534N15 probe (containing sequences specific for the CDK4 gene) showed amplification of the CDK4 gene. These findings indicate that this tumor was no lipoblastoma but an atypical lipomatous tumor, which is of clinical relevance. In young individuals the distinction between lipoblastoma and liposarcoma is often impossible by light microscopy alone. This case shows that FISH can serve as a decisive tool in the differential diagnosis of lipoblastoma and lipoma-like liposarcoma apart from its role in distinction between lipoblastoma and myxoid/round cell liposarcoma.

Ring chromosome 6 may represent a cytogenetic subgroup in benign thymoma

Cytogenetic and fluorescence in situ hybridization analysis of a thymoma revealed the presence of an abnormal clone with a karyotype 46,XY,r(6)(p2?q35?).ish r(6)(p2?q35?)(WCP6+,dJ476O18-,dJ62I11-, PAC59C23+,PAC57H24-),der(21)t(6;21)(p25;q22)(dJ62I11+,cosC9a1-). Histologically, the tumor was encapsulated and classified as thymoma type AB (World Health Organization classification) or mixed thymoma (Muller-Hermelink classification), composed of well-formed lobules with sharp demarcation of both the spindly type A and lymphocyte-rich type B components. This finding, together with literature data, strongly suggests that terminal deletion of the short arm of chromosome 6 is a recurrent aberration in thymoma.

Molecular cytogenetic analysis of clustered sporadic and familial renal cell carcinoma-associated 3q13 approximately q22 breakpoints

We describe several relatives within one renal cell cancer (RCC) family sharing a constitutional t(2;3) (q35;q21). Based on molecular studies on several independent primary tumors in this family, a causative role for this translocation in tumor development was suggested. Subsequent positional cloning of the 3q21 chromosomal breakpoint revealed that this breakpoint disrupts a novel gene, DIRC2 (disrupted in renal cancer 2). This gene encodes an evolutionary conserved transmembrane protein and represents a novel member of the MFS superfamily of transporters. To evaluate whether DIRC2 is also targeted in sporadic RCC cases with cytogenetically defined 3q21 breakpoints, fluorescence in situ hybridization analysis was performed on metaphase spreads and/or interphase nuclei of 12 primary sporadic RCC using genomic clones from a 3q21 breakpoint-spanning contig as probes. Three breakpoints were mapped proximal to the familial breakpoint and nine breakpoints were mapped distal to this breakpoint. Two of the latter breakpoints were mapped in the contig within 1 Mb distance from the familial breakpoint. Because these clustered 3q21 breakpoints do not coincide with the familial 3q21 breakpoint, they most likely affect genes distinct from DIRC2.

Primary cutaneous epidermotropic alveolar rhabdomyosarcoma with t(2;13) in an elderly woman: case report and review of the literature

We report a case of a primary cutaneous alveolar rhabdomyosarcoma presenting on the lower limb of a 60-year old woman. The tumor was characterized by aggregates of round blue cells in an alveolar growth pattern in the dermis and subcutis, with the additional unique finding of epidermotropism. By immunohistochemistry tumor cells were positive for vimentin, muscle-specific actin, desmin, myogenin, and Myo-D1 with focal positivity for CD56, neuron-specific enolase, and S-100 protein. Staining for pan-keratin, HMB-45, melan-A, epithelial membrane antigen, chromogranin, CD99, leukocyte common antigen, and alpha-smooth muscle actin was negative. Interphase fluorescence in situ hybridization analysis from paraffin-embedded tumor demonstrated the presence of the translocation (2;13)(q35;q14) confirming the diagnosis. Further investigations revealed no tumor in the underlying deep soft tissues, and there was no evidence of metastasis in other organs. A local recurrence associated with a metastasis to a regional lymph node on the right groin was treated with an above-knee amputation and local radiotherapy to the groin area. The patient subsequently developed cutaneous metastases in the amputation stump and died 2 years after initial presentation. This case indicates that rhabdomyosarcoma may rarely present in the skin in adults and should be included in the differential diagnosis of primary cutaneous small round blue cell tumors not only in children but also in this age group.

Complex genetic alterations in gastrointestinal stromal tumors with autonomic nerve differentiation

Gastrointestinal stromal tumors (GISTs) with neurogenic differentiation, also referred to as "gastrointestinal autonomic nerve tumors (GANTs)," form an ultrastructurally distinctive subgroup of mesenchymal neoplasms of gastrointestinal tract. Cytogenetic and molecular data of these tumors are limited. In the current study, c-KIT gene sequenc-ing analysis, comparative genomic hybridization (CGH), and interphase fluorescence in situ hybrid- ization (FISH) analysis, utilizing chromosome 14- and 22-specific probes, were performed on five primary ultrastructurally confirmed GANTs. FISH and CGH analysis revealed loss of a whole or part of chromosome 14q in two tumors and of chromo- some 22q, with the common overlapping area of loss at q13, in all five tumors evaluated. c-KIT mu- tations were found in all cases; three tumors carried point mutation and/or deletions of exon 11, and in two tumors, insertion in exon 9 was found. These findings suggest that accumulated genetic changes contribute to the pathogenesis of GANTs and that 22q13 loss may be a characteristic feature of these tumors.

Identification of a karyopherin alpha 2 recognition site in PLAG1, which functions as a nuclear localization signal

The activation of the pleomorphic adenoma gene 1 (PLAG1) is the most frequent gain-of-function mutation found in pleomorphic adenomas of the salivary glands. To gain more insight into the regulation of PLAG1 function, we searched for PLAG1-interacting proteins. Using the yeast two-hybrid system, we identified karyopherin alpha2 as a PLAG1-interacting protein. Physical interaction between PLAG1 and karyopherin alpha2 was confirmed by an in vitro glutathione S-transferase pull-down assay. Karyopherin alpha2 escorts proteins into the nucleus via interaction with a nuclear localization sequence (NLS) composed of short stretches of basic amino acids. Two putative NLSs were identified in PLAG1. The predicted NLS1 (KRKR) was essential for physical interaction with karyopherin alpha2 in glutathione S-transferase pull-down assay, and its mutation resulted in decreased nuclear import of PLAG1. Moreover, NLS1 was able to drive the nuclear import of the cytoplasmic protein beta-galactosidase. In contrast, predicted NLS2 of PLAG1 (KPRK) was not involved in karyopherin alpha2 binding nor in its nuclear import. The residual nuclear import of PLAG1 after mutation of the NLS1 was assigned to the zinc finger domain of PLAG1. These observations indicate that the nuclear import of PLAG1 is governed by its zinc finger domain and by NLS1, a karyopherin alpha2 recognition site.

Hyaline vascular Castleman's disease with HMGIC rearrangement in follicular dendritic cells: molecular evidence of mesenchymal tumorigenesis

Chromosomal aberrations involving chromosome segment 12q13-15 are a common finding in a variety of benign mesenchymal tumors. The target gene encodes for HMGIC, a member of the high mobility group protein family. These proteins act as architectural transcription factors. HMGIC plays a role as a common genetic denominator in benign mesenchymal tumorigenesis. We report a case of hyaline vascular Castleman's disease with intragenic HMGIC rearrangement, due to a clonal cytogenetic aberration involving the long arm of chromosome 12 [46,XX, add(1)(q21),der(6)t(6;12) (q23;q15),add(7)(p22), -9,inv(9)(p11q13),del(12)(q15),+mar] obtained after short-term primary cultures. A combined immunocytologic-cytogenetic approach enabled us to demonstrate the exclusive presence of HMGIC rearrangement in anti-CD21 reactive follicular dendric cells. This finding confirms that a clonal proliferation of follicular dendritic cells occurs in the hyaline vascular variant of Castleman's disease. It also provides a possible molecular pathway explaining stromal overgrowths and stromal neoplasms developing from this disorder.

Preliminary results of the FRO project: chromosomal abnormalities in primary uveal melanoma

Uveal melanoma is the most common primary intraocular tumor in adults in the western world. Recent studies indicate that the presence of cytogenetic abnormalities in tumor cells is strongly linked with prognosis. The purpose of this project is the detection of chromosomal abnormalities in a series of frozen tumors (retrospective study) and of fresh tumor tissues (prospective study) and to correlate these results with other prognostic factors and survival.

Chromosome 9 alterations and trisomy 22 in central chondrosarcoma: a cytogenetic and DNA flow cytometric analysis of chondrosarcoma subtypes

Chondrosarcomas are malignant cartilaginous tumors. Most are located in the medullar cavity (central chondrosarcoma), and a minority develop in a preexisting osteochondroma (peripheral chondrosarcoma). The authors present karyotypes for 37 central, peripheral, juxtacortical, and dedifferentiated chondrosarcomas. Using loss of heterozygosity (LOH) analysis and DNA flow cytometry, the authors previously showed that central and peripheral chondrosarcomas probably evolve by different genetic mechanisms. Peripheral chondrosarcoma is characterized by genetic instability, as was previously shown by a high percentage of LOH and a broad range in DNA ploidy. The authors now show that all peripheral chondrosarcomas tested are aneuploid, combined with many nonspecific chromosomal aberrations. Two juxtacortical chondrosarcomas showed normal chromosome numbers combined with limited structural alterations, substantiating that juxtacortical and peripheral chondrosarcomas are two clinicopathologically different entities with a different genetic background. Central chondrosarcomas were previously found to be peridiploid with limited LOH, most frequent at 9p21. In the current study, chromosome 9 was involved in five of seven central chondrosarcomas compared with only one of four peripheral chondrosarcomas. Three central tumors showed involvement of the 9pl2-22 region, suggesting an important role for chromosome 9 in the oncogenesis of central chondrosarcoma. Moreover, trisomy 22 was found in four central chondrosarcomas only.

Cumulative dosage effect of a RAD51L1/HMGA2 fusion and RAD51L1 loss in a case of pseudo-Meigs' syndrome

Uterine leiomyoma presenting with ascites and pleural fluid is referred to as pseudo-Meigs' syndrome. It is unclear whether common uterine leiomyomas and uterine leiomyomas causing pseudo-Meigs' syndrome are cytogenetically related or whether functionally different primary pathogenetic triggers are responsible for the differences in tumor phenotype. In this study, we investigated the possible involvement of RAD51LI and HMGA2 (formerly known as HMGIC) in initiation and/or progression of a huge uterine leiomyoma presenting as pseudo-Meigs' syndrome. The detailed cytogenetic and FISH analysis revealed the presence of two subclones with a complex karyotype, 46,XX,t(2;12)(q31;q21),ins(14;12)(q23-24;q15q21).ish del(12)(q15q15) (LL12NC01-142H1-,LL12NC01-27E12-),der(12)t(2;12)(LL12NC01-142H1+,LL12NC01-27E12-),der(14)ins(14;12)(q22;q15q15) (LL12NC01-142H1+,LL12NC01-27E12+,RAD51LI+), der(14)ins(14;12)(q23-q24;q15q21) (LL12NC01-142H1-, LL12NC01-27E12+) [20]/46,idem,del(14)(q21q24).ish(RAD51LI-) [6], indicating intragenic HMGA2 rearrangement and loss of one of the RAD51LI alleles in a derivative subclone with chromosome 14 deletion. Furthermore, RACE and RT-PCR analysis of the tumor cells did not reveal abnormal HMGA2 or RAD51LI transcripts. Additionally, the cellular subclone with intrachromosomal 14q21-q24/RAD51LI deletion showed an in vitro growth advantage over the subclone without the deletion. This observation supports a model in which accumulation of two independent mutations-a classical structural rearrangement involving HMGA2 and RAD51L1, in combination with a loss of the second RAD51L1 allele-might play a major role in the development of pseudo-Meigs' syndrome.

Aneurysmal bone cyst of the nose with 17p13 involvement

We report on a 6-year-old girl with a polypoid mass, filling up the entire right nasal cavity as shown on a magnetic resonance imaging scan. Histologically, the tumor had the characteristics of an aneurysmal bone cyst, which is extremely rare in this location. Cytogenetic analysis disclosed a single (6:17)(p21;p13) translocation, confirming a specific genetic involvement in the development of aneurysmal bone cysts. Fluorescent in situ hybridization analysis mapped the putative gene between the p53 (17p13.1) and the Mieller-Dieker gene (17p13.3) loci.

Is 4q13 a recurring breakpoint in solitary fibrous tumors?

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm found predominantly in the subpleural region but also in many other body sites. We report a malignant solitary fibrous tumor of the peritoneum with a 47,XY,t(4;9)(q13;p23),+5 karyotype. The chromosome 4q13 breakpoint in the presented and previously published case of pleural solitary fibrous tumor with a 46,XY,t(4;15)(q13;q26) karyotype was further characterized by fluorescence in situ hybridization analysis and localized within the 5-cM interval that was flanked by regions specific to YAC clones 761A7 and 886C11. Chromosome translocations involving chromosome 4q13 may characterize a separate cytogenetic subgroup of SFT.

Molecular cytogenetic definition of three distinct chromosome arm 14q deletion intervals in gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms characterized by frequent chromosome arm 14q losses. In this study, the 14q changes in a series of 39 histologically and immunohistochemically confirmed GISTs were analyzed in detail by metaphase and/or interphase fluorescence in situ hybridization (FISH) studies using 21 genetically well-characterized, region-specific 14q11-24 YAC clones. By conventional cytogenetic analysis, acquired clonal chromosome aberrations were found in 17 out of 35 tumors. Chromosome 14 was involved in 13 cases; six specimens showed complete chromosome 14 loss, while the remaining seven had structural abnormalities with the breakpoints residing within the intervals 14q11-13 or 14q22-24. Other recurrent chromosome aberrations included frequent deletions of chromosome 1p (11/17), losses of chromosome 22 (7/17), losses or deletions of chromosome arm 13 (6/17) or 15 (4/17), and gains or translocations involving chromosome 17 (4/17). Combining cytogenetic data with double-color FISH analysis, total or partial losses of 14q material were detected in 29 out of 36 tumors (81%). The 14q losses were found in all stages and histological subtypes. Two most frequent common deletion regions flanked by YACs 931B1 and 761D4, and 802E7 and 892C11 at 14q23-24 (25/30 of each; 83%) could be identified. Furthermore, 21 tumors (70%) shared a region of deletion defined by YACs 957H10 and 931E5 at 14q11-12. Our results suggest the presence of at least three distinct critical deletion regions on chromosome 14 in GISTs.

Peripheral primitive neuroectodermal tumor within the spinal epidural space

A case of an epidural spinal peripheral primitive neuroectodermal tumor (pPNET) in a 13-year-old girl is presented. The tumor was disseminated at the moment of diagnosis, thus only diagnostic oligobiopsy of the epidural mass was performed. Histologically the tumor was composed of small round blue cells. The neoplastic cells expressed MIC2 and features of neural differentiation on immunohistochemical staining (neuron-specific enolase, synaptophysin and NCAM positivity). Fluorescent in situ hybridization (FISH) analysis was performed for the final diagnosis and the translocation t(11;22)(q24;q12) was detected. The present case emphasizes the usefulness of FISH in differential diagnosis of tumors, especially when only routinely fixed material is available.

Histologic localization of PLAG1 (pleomorphic adenoma gene 1) in pleomorphic adenoma of the salivary gland: cytogenetic evidence of common origin of phenotypically diverse cells

Pleomorphic adenoma gene 1 (PLAG1), a zinc finger transcription factor gene, is consistently rearranged and overexpressed in human pleomorphic adenomas of the salivary glands with 8q12 translocations. In this report, we describe the immunohistochemical localization of PLAG1 protein in pleomorphic adenomas of the salivary gland and corresponding normal tissue, in relation to cytokeratin, vimentin, and BCL-2 expression. Normal salivary gland tissue was not immunoreactive for PLAG1. In primary pleomorphic adenomas, cells strongly immunoreactive for PLAG1 were detected in the outer layer of tubulo-ductal structures, which are thought to be the origin of cells with bi-directional, epithelial, and mesenchymal phenotypes. In contrast, epithelial cells with abundant cytokeratin in the inner tubulo-ductal structures only sporadically expressed PLAG1. BCL-2 immunoreactivity was found mainly in the cells surrounding the tubulo-ductal structures and in the solid undifferentiated cellular masses, within the areas that had moderate PLAG1 immunoreactivity. The variability of PLAG1 expression in neoplastic cells seemed to reflect the morphologic heterogeneity that correlated with the stage of differentiation of the tumor cells. Immunohistochemical/cytogenetic evaluation of two pleomorphic adenomas with t(3;8)(p21;q12) or t(5;8)(p13;q12) translocations demonstrated the clonal nature of immunophenotypically diverse cells. This finding confirms the theory that pleomorphic adenoma cells share a common single-cell origin, most likely from the epithelial progenitor basal duct cells.

Chromosomal aberrations in malignant gastrointestinal stromal tumors: correlation with c-KIT gene mutation

Gastrointestinal stromal tumors (GISTs) are distinctive, KIT positive mesenchymal neoplasms. The genetic alterations leading to the malignant behavior of these tumors are not well known. In this study, we looked for recurrent numerical chromosomal changes, which may be associated with malignant GISTs, using interphase fluorescence in situ hybridization (FISH). Fourteen malignant primary tumors and two intra-abdominal recurrences were analyzed. Nine benign tumors were studied for comparison. In all cases, the presence of mutations in exons 9, 11 and 13 of the KIT gene were evaluated. Sixteen centromeric enumeration probes (CEP) for chromosomes 1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 15, 16, 17, 18, and X and three locus specific probes (LSI) for 22q11.2 (BCR-locus), 13q14 (RB1-locus) and 14q32 (IgH-locus) were used. The most common changes seen in malignant GISTs were losses of 14q32 and 22q11. However, these changes were commonly detected in benign tumors and represent early changes related to the pathogenesis of GISTs. Losses of chromosomes 1 and 9 were the only recurrent numerical changes seen exclusively in malignant GISTs. Other recurrent numerical changes seen predominantly in malignant tumors were gain of chromosome 8 and losses of chromosomes 7 and 15. The concurrent loss of chromosome 7 and gain of chromosome 8 (in 4 cases) was never seen together with loss of chromosomes 9 or 15 and only once with loss of chromosome 1. Mutations in KIT were found in the majority of malignant GISTs (64%) confirming a previously shown correlation between presence of such mutations and malignancy. KIT mutations were seen in four of five malignant GISTs with loss of chromosome 9, but only in one of four malignant tumors with loss of chromosome 1. These observations may reflect the different pathways leading to malignant transformation of GISTs.

Extra structurally abnormal chromosomes (ESACs)--presentation of 10 new cases

BACKGROUND

The goal of the presented studies as a retrospective reliability assessment of classical banding cytogenetic studies and of prognosing epicrises in a group of 14 cases, affected with additional marker chromosomes.

MATERIAL AND METHODS

Having collected the study material from peripheral blood, by means of trophoblast biopsy or amniocentesis, cytogenetic preparations were obtained, allowing for pre- or postnatal evaluation of the karyotype. A panel of auxiliary cytogenetic techniques accompanied the routine CTG protocol.

RESULTS

In a group of 6875 persons with recommendations to pre- or postnatal cytogenetic diagnostics, 14 (0.2%) cases of ESACs were diagnosed. In 5 cases of DA/DAPI(+) inv dup (15) as observed. A presence of polymorphic interstitial RHG(+) band was found within the marker chromosome. The measured size of that band allowed associating it with either the presence or the absence of pathological signs. In 9 cases of ESACs, DA/DAPI(-), the application of banding techniques (NOR and CBG) allowed to discover bisatellite heterochromatic ESACs in 6 cases (2 non-mosaic and 4 mosaic). In three other mosaic and non-satellite cases of ESACs, a 'genetic inactivity' of the marker chromosome was observed in one case, while a 'genetic activity' was ascertained in two cases. The 'activity' of marker chromosomes was studied by means of replication banding techniques.

CONCLUSIONS

At the time of the outburst of molecular techniques, still up-to-date is the use of classical banding techniques and of the replication techniques, allowing DNA replication kinetics studies at the level of single band.

Acral myxoinflammatory fibroblastic sarcoma with unique clonal chromosomal changes

Acral myxoinflammatory fibroblastic sarcoma is a rare tumor of the distal extremities. We present the hitherto unreported karyotypic abnormalities of this new entity. The tumor presented as a mass in the dorsum of the foot in a 53-year-old woman and showed the typical virocyte-like and lipoblast-like cells in a myxoid and inflammatory background. Cytogenetic analysis revealed a complex karyotype with a reciprocal translocation t(1;10) (p22;q24) in addition to the loss of chromosomes 3 and 13. Fluorescence in situ hybridization with the 769E11YAC and BAC 31L5 and 2H23 probes showed the breakpoint to be located proximally to BCL10 and distally to GOT1 genes on chromosomes 1p22 and 10q24, respectively. The presence of these clonal chromosomal changes supports the neoplastic nature of acral myxoinflammatory fibroblastic sarcoma and underscores that it represents a separate entity.

Calcifying/ossifying synovial sarcoma shows t(X;18) with SSX2 involvement and mitochondrial calcifications

AIMS

Synovial sarcoma with extensive calcification and ossification is a rare variant, the ultrastructural, cytogenetic and molecular analysis of which has not been reported previously.

METHODS AND RESULTS

A large mass in the shoulder of a 20-year-old male patient led to a deformity of the chest wall, thus supporting the hypothesis that this is a slowly growing variant of synovial sarcoma. Nevertheless, the patient developed metastatic lung disease 7 months after resection. On histology, the monophasic spindle cell proliferation was in several areas obscured by the massive calcification and ossification. Immunohistochemistry showed keratin, epithelial membrane antigen, vimentin and CD99 expression. The cytogenetic analysis revealed a single t(X;18)(p11.2; q11.2), typical for synovial sarcoma. Additional fluorescence in-situ hybridization revealed SSX2 involvement. At the ultrastructural level, prominent needle-shaped intramitochondrial crystals were present, both in the cytoplasm and in the extracellular matrix.

CONCLUSION

The presence of the t(X;18) with SSX2 involvement definitively characterizes this tumour as a variant of synovial sarcoma. In addition, the needle-like mitochondrial calcifications give a possible clue to the pathogenesis of the extensive metaplastic ossification and calcification.

[Familial occurrence of nephroblastoma]

Wilms' tumour can develop in ways: sporadic--non-hereditary or familial. Familial Wilms' tumour is not very seldom. It is a form of autosomal dominant segregation and probably low and variable penetration. Up to now it has not been observed in the presence of characteristic genetic changes. Taking into consideration the case of the patient with positive family interview we presented the way of diagnosing and treating the child. Moreover we presented the results of cytogenetic examination and molecular analyses (loss of heterozygosity of WT1 gene and loss of heterozygosity 16 q), which had not shown any changes. We also discussed the actual level of knowledge abut familial form of Wilms' tumour.

Angiomyxolipoma shares cytogenetic changes with lipoma, spindle cell/pleomorphic lipoma and myxoma

Angiomyxolipoma is a rare variant of lipoma, two cases of which have recently been described. We report on the hitherto unreported clonal chromosomal changes of a third case of angiomyxolipoma. The karyotype showed a 46,XX,t(7;13)(p15;q14),t(8;12)(q13;p13)[17]/46,XX[3]. The involvement of 13q14, 12p13, and 8q13 supports a relationship with other types of benign lipomatous and myxoid tumors.

Common chromosome aberrations in the proximal type of epithelioid sarcoma

A new case of the proximal type of epithelioid sarcoma with a complex karyotype 70-98 <4N>,XX,-X,-X,+5,i(5)(q10),+7,del(7)(q31),i(8)(q10)x3 approximately 4,del(12)(p13),der(18)ins(18:?) (q11;?)del(18)(p11). ish der(18)ins(18;X)del(18)(p11)(wcp18+,wcpX+),+20,+20,dmin [cp9] is described. Both, dual-color FISH using probes specific for OATLI1/OATL2 genes and RT-PCR analysis excluded the presence of t(X;18), typical for synovial sarcoma. Our case together with the previously published ones suggest that the presence of i(8)(q10), losses of 12p and 18p together with the gain of chromosome 20 may represent a common cytogenetic aberrations in the proximal type of epithelioid sarcoma.

DNA adduct formation in human and rat mammary epithelium by N-hydroxy derivatives of 2-aminofluorene and 4-aminobiphenyl

Primary cultures of rat mammary epithelium and the human mammary cell line MCF-12 were incubated with 10 microM N-formyl-, N-acetyl-, or N-propionyl-derivatives of N-hydroxy-2-aminofluorene (N-OH-AF) or N-formyl-, or N-acetyl derivatives of N-hydroxy-4-aminobiphenyl (N-OH-ABP), in the medium with or without 100 microM paraoxon, for 3 h. Carcinogen-DNA adducts in the nuclei were detected with an immunohistochemical method using polyclonal antibodies against N-(deoxyguano-8-yl)-2-aminofluorene and ABP-DNA adducts. The relative amounts of adducts per nucleus were determined by image analysis. After treatment, more than 90% of the cells that were attached on the coverslip were alive, as determined by the trypan blue exclusion. All carcinogens produced adducts in both human and rat cells. Adduct formation by the formyl, but not the acetyl or porpionyl, derivatives was inhibited up to 65% by paraoxon. These results demonstrate that both acetyl and propionyl derivatives are primarily activated by cytosolic acetyltransferases and the formyl derivatives may be equally activated by the acetyltransferases and microsomal carboxylesterases. Additionally, the results suggest that exposure to aromatic amines may be a risk factor for human breast cancer.

Cytogenetic and proliferative potentials in meningiomas

Cytogenetic analysis and Ki-67 staining index (SI) were performed on the series of 51 meningiomas, to estimate the relationship between the extent of chromosomal changes and the growth potential of tumors. The tumors were classified according to histological subtype (22 meningiotheliomatous, 15 transitional, 12 fibroblastic and 2 angiomatous) and grade (40 benign, 5 atypical and 6 malignant ones). There was no significant difference in the complexity of chromosomal changes among the histologically distinct tumor subtypes. In contrast, there was a significant association between the number of chromosomal abnormalities and tumor grade. Normal karyotypes were found in 50% and complex in 20% of benign tumors. All grade II or III tumors revealed complex karotype. The tumors classified as benign revealed significantly lower mean Ki-67 SI than atypical or malignant ones (1.6%, 7.4% and 14.7%, respectively). However, within tumors classified as benign, mean Ki-67 SI of these with normal or simple karyotypic changes did not differ significantly from those with complex karyotype (1.6% and 0.9%, respectively). Thus, the extent of genome abnormalities in meningiomas, measured on the chromosomal level, does not relate directly to their proliferative potential.

16q heterozygosity loss in Wilms' tumour in children and its clinical importance

INTRODUCTION

The loss of heterozygosity (LOH) of 16q is a structural change detected in about 20-30% of Wilms' tumour cases. Aberrations which result in deletion of 16q are also found in breast cancer, prostate cancer and liver cancer, where they are connected with a worse prognosis. The hypothesis of a bad prognosis in nephroblastomas with LOH 16q was first formulated by scientists from NWTS (National Wilms Tumor Study) on the basis of 232 cases of Wilms' tumour. However, SIOP studies (International Society of Paediatric Oncology) which included 28 cases of Wilms' tumour, did not show any clinico-pathological correlations with LOH 16q. Therefore, we aimed to evaluate the importance of LOH 16q in relation to clinico-pathological factors in a group of children, treated according to the SIOP criteria.

AIMS

The aim of this work was to evaluate the frequency of LOH 16q in sporadic unilateral Wilms' tumour and to study the relationship between LOH 16q and selected patho-clinical parameters. The study comprised 66 children (31 girls and 35 boys) aged from 2 days to 13 years.

METHODS

LOH 16q was studied by the examination of polymorphism of marker sequences in the region 16q24. DNA was isolated from paraffin sections of tissue for routine microscopic examination by the microdissection method. The method of study involved the amplification of polymorphic sequences from the 16q24 region by polymerase chain reaction (PCR) and separation of the products of amplification by polyacrylamide gel electrophoresis. The results were the subject of statistical analysis in relation to gender, age of child at first diagnosis, stage of clinical advancement and histological type of tumour. The connection between LOH 16q and recurrences, metastases and death, and failure free survival and absolute survival of children followed-up for over 24 months after nephrectomy were studied.

RESULTS

The study revealed a lack of correlation between LOH 16q and gender, however LOH 16q was more frequent in children with Wilms' tumour aged >24 months, P<0.05. Also, LOH 16q was more frequent in tumours classified as clinical stage (CS) II or III than in CS I, P<0.05, but there were no differences in the occurrence of LOH 16q in tumours classified as CS II and CS III. We have found no correlation between LOH 16q and the histological type of tumour. However, LOH 16q has been found three times as frequently in tumours from children who died than in tumours of children who survived, P<0.0024.

A comparative study of P53/MDM2 genes alterations and P53/MDM2 proteins immunoreactivity in soft-tissue sarcomas

In the present study, the expression of P53 and MDM2 proteins were examined in 94 soft-tissue sarcomas (35 malignant fibrohistiocytomas, 15 neurosarcomas, 14 liposarcomas, 13 leiomyosarcomas, 11 fibrosarcomas and 6 dermatofibrosarcomas) by immunohistochemistry. The immunohistochemical findings were correlated with P53 mutation analysis using PCR-SSCP, PCR-HDF and direct sequencing, and MDM2 amplification studies by differential PCR. P53 immunopositivity was found in 25 out of 94 (26.6%) cases. Alterations of the P53 gene were detected in 12 (12.8%) tumors; eight of these tumors revealed P53 immunoreactivity. A high number of P53 positive and P53 mutated tumors were histologically defined as poorly differentiated G3 (64.0% and 75.0%, respectively). MDM2 immunopositivity was revealed in 36 out of 94 (38.3%) cases. MDM2 amplification occurred in 17 tumors (18.1%); only nine of these tumors exhibited MDM2 immunoreactivity. Overall, MDM2 positivity was not associated with MDM2 amplification in 27 out of 94 tumors (28.7%). There was no significant correlation between MDM2 overexpression and histological grade. However, when the samples were stratified by immunophenotype, the majority of tumors (52.5%) with isolated MDM2 overexpression (dissociated from P53 positivity) were defined histologically as low grade (G1 + G2). These results support the notion that besides P53 alterations, MDM2 gene deregulation seems to be an important event in sarcomas evolution. Additionally, the mechanism of MDM2-mediated degradation of P53 protein, without involving stabilization and inactivation of P53 gene, should be considered for better understanding of all features of tumor progression processes.

Histological localization of acetyltransferases in human tissue

The localization of human arylamine acetyltransferases (NAT) transcripts was performed by non-isotopic in situ hybridization, utilizing a combination of six NAT1 or NAT2 specific antisense oligonucleotide probes, in order to identify those tissues and organs that might be susceptible to the carcinogenic effects of aromatic amines. The intratissue differences in the level of NAT mRNA were observed: the most abundant NAT2 transcripts were found in hepatocytes, while NAT1 ones dominated in the urothelium and in the colon epithelial cells. The specific NAT1 and NAT2 mRNAs were present also in the epithelial lining of the lung bronchi, the mammary gland and the small intestine epithelial cells, the outer layer of placenta syncytiotrophoblast cells, the kidney tubules, and the pineal gland. Qualitative differences in the sites of mRNA of these two enzymes were seen only in the kidney specimens, in which NAT2 was expressed in both proximal and distal tubules, and the NAT1 was detected only in the former ones.

Atypical chronic myelogenous leukemia following immunosuppressive therapy for severe aplastic anemia

Late clonal complications of aplastic anemia (AA) such as acute leukemia, myelodysplastic syndromes or paroxysmal nocturnal hemoglobinuria have been recognized for a long time. To our knowledge, chronic myelogenous leukemia (CML) as a late complication of severe aplastic anemia has as yet not been reported. We report here a case of AA treated successfully with antilymphocytic globulin and cyclosporin in whom Ph1 negative, BCR/ABL negative CML developed 8 years after diagnosis of AA. This case of atypical, secondary CML was refractory to treatment with interferon alpha and hydroxyurea.