Aberrations of chromosome 19. Do they characterize a subtype of benign thyroid adenomas?

We describe the cytogenetic findings in two benign thyroid hyperplasias with aberrations of chromosome 19. In the first patient, two of four nodules showed identical translocations involving chromosome 19 and 22: 46,XX,der(19)t(19;?)(q13;?),der(22)t(22;?)(q12;?), the remaining nodules had an apparently normal karyotype. Two nodules from a second patient were karyotyped. One showed a karyotype 46,XX,t(1;19)(p35-36.1;q13) and the other had a normal karyotype. From these results as well as those reported previously, we can conclude that structural changes of chromosome 19 characterize a subgroup of thyroid adenomas, thyroid hyperplasias, or both.

Deletion of part of the long arm of chromosome 13 as the only karyotypic aberration in a follicular thyroid adenoma.

A follicular thyroid adenoma is described showing a del(13)(q14) as the only karyotypicabnormality. The karyotypic similarities to another benign tumor, the lipoma, are discussed.

Cytogenetic biclonality corresponding to multiphasic differentiation in an atypical thyroid adenoma.

Cytogenetic aberrations have been described in about 30% of benign thyroid tumors, but their role for tumorigenesis or progression has not yet been elucidated. We describe the cytogenetic analyses in a thyroid adenoma with two different clonal cytogenetic stemlines: 45,XX,der(1)t(1;14)(p13;q11.2-q(13),t(5;12)(q11.2;q24),del(9)(q12),- 10,der(11)t(11;?;19)(p15;q13),der(14)t(14;15)(q11.2-q13;q23),del(15)(q23 ), der(15)t(9;15)(q12;p10),der(19)t(10;19)(q11.2;q13)/46,X,?inv(x),?inv(3) (p21q29),t(3;8)(q26;q12). Histologic examination revealed an atypical follicular thyroid adenoma containing microfollicular, follicular, trabecular-solid, and oncocytic components. There may be a direct relation between the different cytogenetic stemlines and the histologic diversity of the tumor. Thyroid tumors with complex karyotypes involving the 19q13 breakpoint may represent advanced stages of karyotypic evolution and therefore warrant an extensive clinical follow-up.

Structural abnormalities of chromosome 2 in benign thyroid tumors. Three new cases and review of the literature.

Here we report our cytogenetic findings on three cases of nodular goiter, all showing structural clonal abnormalities of chromosome 2. In the first case, we found a t(2;3)(q21;q27 or q28) in two nodules of the same patient. The second case revealed a t(2;20;3)(p21;q11.2;p25), and the third case showed a t(1;2)(p22;p13). When the data from the literature and the present cases are summarized, the results suggest the existence of at least three breakpoint clusters of chromosome 2 in benign thyroid tumors or hyperplasias.

Cytogenetic subtyping of 220 salivary gland pleomorphic adenomas: correlation to occurrence, histological subtype, and in vitro cellular behavior.

Based on the hypothesis that three main cytogenetic subtypes of salivary gland pleomorphic adenomas can be distinguished which may also represent different etiologic entities, we investigated whether these subtypes correspond to clinical, histologic, or biologic features of 220 tumors karyotyped (including 117 tumors with detailed clinical history and histologic subtyping). The following results were obtained. As compared with the group of patients showing salivary gland pleomorphic adenomas with an apparently normal karyotype, the patients in the "8q12-group" were significantly younger (51.1 years versus 39.3 years, p < 0.001). The distribution of histologic subtypes also showed highly significant differences between the groups. Whereas the breakpoint in the 8q12 group was always mapped to a single band, no exact localization of the breakpoint in the group of tumors showing chromosome number 12 abnormalities was possible. In most cases, however, the breakpoints were clustered to 12q15. Finally, all tumors with 8q12 breakpoints showed a characteristic in vitro cellular morphology which was also observed in a few tumors with an apparently normal karyotype but in none of the tumors with the 12q13-15 breakpoint.

Cytogenetic tetraclonality in a rare spindle cell variant of an anaplastic carcinoma of the thyroid.

We report a case of an unusual anaplastic carcinoma with spindle cell differentiation in an 85-year-old patient. Although the tumor showed sarcoma-like features its occurrence in the thyroid of an elderly person supported the diagnosis of an anaplastic carcinoma. This diagnosis is also supported by the results of cytogenetic studies that revealed four independent clones. Of these, three clones showed complex chromosomal rearrangements including translocations, deletions and inversions while the remaining clone only showed two balanced translocations. The patient is still alive after 13 months.

Leiomyoma cells with 12q15 aberrations can be transformed in vitro and show a relatively stable karyotype during precrisis period.

Tumor cells from three uterine leiomyomas showing translocations involving 12q14-15 were transformed by transfection using the "early regions" of the SV40 genome. The cells had a higher proliferative capacity, were able to form colonies in soft agar, and showed an increased growth potential. Karyotype analyses of these transformed leiomyoma cells showed that the cells had retained the initial t(12;14) and t(12;15).

An endometrial polyp with a rearrangement of HMGI-C underlying a complex cytogenetic rearrangement involving chromosomes 2 and 12.

Cytogenetic studies of an endometrial polyp of an 82-year-old patient revealed a karyotype 46,XX,der(2)inv(2)(p25q21)ins(2;12)(p25;q13q14)t(2;12)(q21; q15),der(12)del(12)(q13q14)del(12)(q15). By fluorescence in situ hybridization (FISH) we found the chromosome 12 translocation breakpoint to be mapping within the third intron of the HMGI-C gene also harboring the breakpoints of translocations involving 12q15 seen in uterine leiomyomas, lipomas, pleomorphic adenomas, and pulmonary chondroid hamartomas.

Structural aberrations of chromosome 6 in three uterine smooth muscle tumors.

Clonal karyotypic alterations of chromosome 6 in three uterine smooth muscle tumors are reported. In all cases an apparently identical breakpoint on the short arm of chromosome 6 was found. Two cases displayed the histologic features of cell-rich myomas with severe nuclear atypia but no clear evidence for malignancy. The remaining case was a primary uterine leiomyosarcoma of an 80-year-old patient showing an apparently balanced reciprocal chromosomal translocation, t(1;6)(p32-33;p21.3), as the sole karyotypic abnormality. This type of aberration has not been reported before in leiomyosarcomas. Because of the nuclear atypia in the other myomas with a breakpoint involving the short arm of chromosome 6 we feel that this cytogenetically recognizable but rare subgroup of uterine smooth muscle tumors warrants a careful clinical follow-up.

Cytogenetic investigations of 340 thyroid hyperplasias and adenomas revealing correlations between cytogenetic findings and histology.

Cytogenetic analyses were performed on 340 follicular thyroid adenomas and goiters after short-term culture. Clonal chromosomal changes were found in 67 cases. Trisomy 7 as the sole abnormality or along with other trisomies was the most frequent type of aberration (19 cases). Other recurrent numerical changes were loss of chromosome 22 (4 cases) and the second X or the Y chromosome (5 cases). Translocations involving 19q13 (12 cases) were frequent structural chromosomal changes. Dicentric chromosomes or telomeric associations were frequent in goiters (12 cases). After a histopathologic classification of all cases, we have correlated the cytogenetic findings with the histology of the tumors. Only 8.4% of the goiters showed clonal abnormalities, whereas 44.9% of the adenomas revealed clonal abnormalities. Furthermore, simple clonal changes were predominantly found in goiters and complex changes in adenomas. The most impressive correlation was found in the group of lesions with trisomy 7. Although all but one lesion with one or two additional trisomies were goiters, those having three or more additional trisomies were all adenomas or adenomatous goiters.

Inhibition of bcl-2 enhances the efficacy of chemotherapy in renal cell carcinoma.

OBJECTIVES: Renal cell cancer (RCC) is highly resistant to chemotherapy. Increased expression of the antiapoptotic gene bcl-2 in tumors is known to be associated with poor responses to systemic treatment of cancer. Down-regulation of bcl-2 expression using antisense oligonucleotides (asON) has been shown to increase chemosensitivity in clinical phase I-III studies with various cancers. However, no studies on the efficacy of this approach in RCC have been reported so far. This study aimed to evaluate whether bcl-2 asON could enhance efficacy of chemotherapy in human RCC. MATERIAL AND METHODS: Expression of bcl-2 mRNA and protein was analyzed in different RCC cell lines by RT-PCR and Western blot. Cells with high or low bcl-2 mRNA and protein expression were treated with different concentrations of bcl-2 asON in combination with cisplatin. AsON-induced down-regulation of bcl-2 mRNA and protein was documented by RT-PCR and Western blot. Treatment effects on cell viability were analyzed by colorimetric tetrazolium (MTT) assay. Immunohistochemical staining of M30-positive cells was performed for quantification of apoptotic cells. RESULTS: Transfection of high bcl-2 expressing cells with bcl-2 asON alone induced no reduction of cell viability at a concentration range from 100-1000 nM. In combination therapy, pretreatment with asON significantly enhanced MTT reduction after cisplatin treatment. IC50 concentrations of cisplatin were 1 microg/ml with and 2.7 microg/ml without prior incubation. The marked reduction of cell viability correlated with an 8-fold increase of apoptotic cells after combination treatment. Only a minor increase of cisplatin effectivity was noted after asON preincubation of cells with lower bcl-2 expression. CONCLUSIONS: The combination of cisplatin and bcl-2 antisense ON exerts significantly greater effects on cell viability and apoptosis than either agent used alone on human RCC cells. These data indicate that inhibition of bcl-2 expression may be an attractive therapeutic strategy in RCC tumors with high bcl-2 expression.

[Cytogenetic subtyping of 139 uterine leiomyoma]. / Eine zytogenetische Subtypisierung von 139 Uterus-Leiomyomen.

A cytogenetic study of 139 uterine leiomyomas of 70 patients is presented. 26 of the tumours failed to grow, 87 showed an apparently normal karyotype and 26 tumours were characterised by clonal aberrations. In 5 tumours, a numerical change was the only abnormality, including 2 tumours with a trisomy 12. 5 myomas showed an interstitial deletion of the long arm of chromosome 7. The largest group were 9 tumours with an aberration involving chromosome 12 in the band of 14-15. 2 myomas showed a t(12; 14) as the only abnormality, in 4 tumours very complex rearrangements with up to 12 breakpoints were observed. In the last group 7 myomas with other clonal aberrations involving 11 different chromosomes were found.

Pleomorphic adenoma cells vary in their susceptibility to SV40 transformation depending on the initial karyotype.

Chromosomal aberrations involving 8q12 or 12q13-15 characterize two cytogenetic subgroups of salivary gland pleomorphic adenomas. As the tumors of the two groups differ in their clinical and histologic characteristics, we decided to determine their susceptibility to SV40 transformation. We transfected cell cultures from 13 adenomas with aberrations involving 8q12 and from seven adenomas with involvement of 12q13-15 using an SV40 plasmid coding for the early region of the viral genome. Whereas all cultures with aberrations of 12q13-15 showed transformed foci, only 4 of the 13 cultures with 8q12 abnormalities showed foci of transformed cells. We also observed a much higher immortalization rate in the first group (3/7 vs. 1/13). All successfully transformed tumor cell cultures showed a relatively stable karyotype in the pre-crisis stage and a high mitotic index, were T-antigen positive, and had an extended life span in vitro.

A characteristic sequence of trisomies starting with trisomy 7 in benign thyroid tumors.

The cytogenetic results from a series of 113 thyroid hyperplasias and adenomas are reported; 15 showed clonal karyotypic alterations. In addition to a group showing translocations involving 19q13, another subset of lesions characterized by polysomies can be found. Based on our own cases belonging to this subset and a review of the cases reported in the literature, we conclude that the characteristic feature of this group is a sequence that always starts with trisomy 7, but that sometimes even leads to chromosome numbers in the hypertriploid range. This subset of thyroid tumors may be an example of a more common genetic pathway in human solid tumors.

Deletions of the short arm of chromosome 2 characterize a new cytogenetic subgroup of benign thyroid tumors.

Cytogenetic studies of thyroid hyperplasias and adenomas have shown that besides cases with an apparently normal karyotype different groups of cytogenetic abnormalities exist. Herein we describe the cytogenetic analyses of two benign thyroid tumors with deletions of the short arm of chromosome 2. A similar case has been described previously. Besides the previously well-established subgroups, alterations of chromosome 2 may thus characterize a new cytogenetic subgroup of benign thyroid tumors.

Chromosomal translocations affecting 12q14-15 but not deletions of the long arm of chromosome 7 associated with a growth advantage of uterine smooth muscle cells.

Cytogenetically, uterine leiomyomata are the best investigated human tumours. The most frequent clonal abnormalities are structural rearrangements involving 12q14-15 and deletions of part of the long arm of chromosome 7. The present study investigated a possible growth advantage conferred by these abnormalities, when compared with myomata having an apparently normal karyotype. A total of 155 myomata were included in the study. All samples were obtained after hysterectomy enabling karyotype analysis of all detectable tumours. Myomata with clonal chromosome abnormalities were significantly larger than those with a normal karyotype (6.8 +/- 5.3 versus 3.4 +/- 2.1 cm; P < 0.001). However, when differentiating between the two main aberrations, this was found to be true for the myomata with 12q14-15 changes affecting the high mobility group protein IC (HMGIC) gene (8.9 +/- 5.6 cm), but not for the group of tumours characterized by deletions of chromosome 7 (3.5 +/- 2.0 cm). The results are compatible with the hypothesis that myomata develop due to an unknown event, whereas the chromosomal abnormalities act as secondary changes, with those affecting the HMGIC gene increasing the growth potential of the corresponding tumours.

[Cytogenetic changes in benign thyroid gland hyperplasias and adenomas correlated with histology]. / Zytogenetische Veränderungen bei benignen Schilddrüsenhyperplasien und Adenomen korrelieren mit der Histologie.

In order to elucidate cytogenetic changes associated with the development of benign growth of follicular epithelial cells of the thyroid, cytogenetic analyses were performed on 340 follicular thyroid adenomas and goiters after short-term culture. Clonal chromosome changes were found in 67 cases. Trisomy 7 as the sole abnormality or along with other trisomies was the most frequent type of aberration (19 cases). Other recurrent numerical changes were loss of chromosome 22 (4 cases) and the second X or the Y chromosome (5 cases). Translocations involving 19q13 (12 cases) were frequent structural chromosome changes. After a histopathological classification of all cases, we have correlated the cytogenetic findings with the histology of the tumors. Only 8.4% of the goiters showed clonal abnormalities whereas 44.9% of the adenomas revealed clonal abnormalities. Furthermore, simple clonal changes were predominantly found in goiters and complex changes in adenomas. The most impressive correlation was found in the group of lesions with trisomy 7: Whereas all but one lesion with one or two additional trisomies were goiters, those having three or more additional trisomies were all adenomas or adenomatous goiters.

Follicular thyroid carcinoma: chromosome analysis of 19 cases.

Short-term cultures of 19 follicular thyroid carcinomas were examined cytogenetically. Clonal chromosomal changes were detected in 12 tumors. Two follicular carcinomas had only numerical alterations: one with a hyperdiploid karyotype with trisomies/polysomies of chromosomes 7 and 12, similar to the karyotypes previously identified in a sub-group of benign thyroid lesions, and the other with monosomy 20. In the remaining ten cases several structural chromosome anomalies were found. Loss of the short arm of chromosome 3 was observed in one tumor. In two widely invasive and metastasizing follicular carcinomas there was a t(7;8)(p15;q24) as the sole abnormality in one case and a der(8)t(7;8)(p15;q24) together with other cytogenetic alterations in the other case. This finding suggests that t(7;8)(p15;q24) may be related to an aggressive behavior of follicular thyroid carcinomas.