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We aimed to characterize the genomic profiles of adenocarcinomas in the gastroesophageal junction in relation to cancers in the esophagus and the stomach. Profiles of gains/losses as well as gene expression profiles were obtained from 27 gastroesophageal adenocarcinomas by means of 32k high-resolution array-based comparative genomic hybridization and 27k oligo gene expression arrays, and putative target genes were validated in an extended series. Adenocarcinomas in the distal esophagus and the gastroesophageal junction showed strong similarities with the most common gains at 20q13, 8q24, 1q21-23, 5p15, 13q34, and 12q13, whereas different profiles with gains at 5p15, 7p22, 2q35, and 13q34 characterized gastric cancers. CDK6 and EGFR were identified as putative target genes in cancers of the esophagus and the gastroesophageal junction, with upregulation in one quarter of the tumors. Gains/losses and gene expression profiles show strong similarity between cancers in the distal esophagus and the gastroesophageal junction with frequent upregulation of CDK6 and EGFR, whereas gastric cancer displays distinct genetic changes. These data suggest that molecular diagnostics and targeted therapies can be applied to adenocarcinomas of the distal esophagus and gastroesophageal junction alike., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)

The malignant transformation that characterizes the development of Barrett esophagus-associated adenocarcinomas is a multi-step process in which genetic alterations in various tumor-associated genes accumulate. Defective mismatch repair (MMR) is the cause of microsatellite instability (MSI) pathway that characterizes a subset of gastrointestinal tumors and is specifically associated with tumor development within the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome. The few studies that have assessed MMR defects in Barrett-associated adenocarcinomas have reached different results. We therefore assessed the expression of the MMR proteins MLH1 and MSH2 in a series of 59 Barrett adenocarcinomas and found a loss of MMR protein immunostaining in 2/59 (3%) tumors; one tumor showed a loss of MSH2 expression, the other tumor showed a loss of MLH1, and both tumors displayed an MSI-high phenotype. Our findings suggest that only a small subset of Barrett adenocarcinomas develop because of defective MMR, but demonstrate that MLH1 and MSH2 are the primary targets for defective MMR also in this tumor type.

The majority of tumors from patients affected by hereditary nonpolyposis colorectal cancer (HNPCC) exhibit a mutator phenotype characterized by widespread microsatellite instability (MSI) and somatic mutations in repeated sequences in several cancer-associated genes. An inverse relationship between MSI and chromosomal instability (CIN) has been demonstrated and HNPCC-associated tumors are generally characterized by diploid or near-diploid cells with few or no chromosomal rearrangements. We have studied MSI, somatic mutations in repeat-containing genes, DNA-ploidy, and cytogenetic aberrations in a colon carcinoma from a patient with a germline MLH1 mutation. Mutations in coding repeats were assessed in 10 macroscopically separate areas of the primary tumor and in two lymph nodes. Some of the genes studied (E2F4, MSH3, MSH6, TCF4, and TGFBRII) showed a consistent lack of mutations, whereas others (BAX, Caspase-5 and IGFIIR) displayed alterations in some tumor regions but not in others. The tumor had DNA-index 1.1-1.2 and a stable, aberrant karyotype with extra copies of chromosomes 7 and 12 and the structural aberrations i(1q), der(20)t(8;20), and der(22)t(1;22). The finding of CIN, MSI, and somatic mutations in coding repeats in this tumor suggests that these phenomena may act together in HNPCC tumorigenesis. Furthermore, the observed intratumoral heterogeneity of mutations in coding repeats implies these changes occur late in tumorigenesis and, thus, probably play a role in tumor progression rather than initiation.

Cytogenetic investigation of short-term cultures from two leiomyosarcomas revealed complex karyotypic changes in both cases. The first tumor, a subcutaneous leiomyosarcoma of the knee, had the karyotype 70-80,XY, +X, +Y, +1, +1, +2, +2, +3, +3, +4, +4, +7, +7, +8, +8, +9, +10, +15, +15, +16, +16, +18, +19, +20, +21, +21, +22, +22,t(?;5)(5;21)(?;q35p11;q11), t(?;5)(5;21)(?;q35p11;q11), +del(11)(q22),der(13)t(12;13)(q13;q22),der(14)t(9;14)(p11;p11), +14p+, +t(20;?)(q13;?), +t(20;?)(q13;?), +2 mar. A polyploidized clone with 120-150 chromosomes was also observed. DNA flow cytometry revealed only one abnormal peak, corresponding to a DNA index of 1.76. The other tumor, a uterine leiomyosarcoma, had the karyotype 61-67, X, -X, +1, +3, +5, +6, +7, +8, +9, +12, +13, +15, +t(1;1)(p32;q32), +der(1)t(1;8)(p13;q11), +del(2)(p11), +del(2)(q22), +del(2)(q22), +del(3)(p13), +i(5p),t(8;14)(q24;q24), +der(8)t(8;14) (q24;q24), +del(10)(p12),der(11)t(11;15)(p15;q11),t(16;?)(p13;?),t(16;?)(q24;?), der dic(17) (17pter----cen----17q25::hsr::17q25----cen----17pte r), +t(19;?)(p13;?), +der dic(20)(20pter----cen----20q12::hsr::20q12----cen----+ ++20pter), +mar. The DNA index was 1.59. The finding in these leiomyosarcomas of rearrangements of the same regions of chromosomes 12 and 14 that are involved in the tumor-specific t(12;14)(q14-15;q23-24) of uterine leiomyoma indicates that the same genes in 12q and 14q might be important in the pathogenesis of benign and malignant smooth muscle tumors.

Chromosome analysis of short-term cultures from uterine leiomyomas revealed trisomy 12 in six cases. In four of the tumors + 12 was the only karyotypic change. The fifth case also had trisomy 4, whereas the sixth had loss of one X chromosome as an additional aberration. These findings indicate that trisomy 12 characterizes a new cytogenetic subgroup of uterine leiomyoma.

Cytogenetic analysis of short-term cultures from two uterine sarcomas revealed clonal chromosome abnormalities in both cases. A locally recurrent mixed mesodermal tumor had the karyotype 61,XX,+2,+3,+del(5)(q11),+6,+7,+del(7)(q32),+8,+8,+8,+10, -11,-11,+der(11)t(1;11)(q12;p15),+der(11)t(1;11)(q12;p15),+der(11)t(1;11)(q12;p15),+del(12)(q14q21),+13,+15,del(17)(q23),+20. The other tumor, a lung metastasis from a uterine leiomyosarcoma, had several karyotypically abnormal clones. Two of them consisted of highly aberrant cells with modal chromosome numbers of 82 and 153, respectively, but because of insufficient quality the complex anomalies could not be identified. Various chromosomal changes that included translocations, deletions, insertions, and numerical rearrangements (always with extra chromosome 7 material) were identified in pseudo- or near-diploid cells, resulting in nine additional cytogenetically abnormal clones.

We have cytogenetically investigated short-term cultures initiated from 34 uterine leiomyomas, all of which were histologically completely benign. Clonal chromosome abnormalities were detected in five cases, a normal female complement in 22, whereas, in the remaining seven tumors no karyotype could be established. Apparently identical reciprocal translocations, t(12;14)(q14-15;q23-24), were found as the sole abnormality in four tumors. The fifth abnormal case contained a t(2;14)(p11;p11). We conclude that chromosome aberrations may be found in myomas of the uterus, and that t(12;14)(q14-15;q23-24) characterizes a subset of these tumors.

Cytogenetic studies of two uterine leiomyomas from the same patient revealed different karyotypic changes. Both tumors showed only a single chromosome abnormality; one had t(1;6)(q23;p21) and the other del(7)(q21.2q31.2). These findings support the view that multiple leiomyomas of the uterus arise independently.

We have studied three uterine leiomyoma tumors, all previously cytogenetically analyzed and shown to have the clonal abnormality t(12:14)(q14-15;q23-24), with the purpose of detecting amplification or rearrangement of three genes that are localized close to the 12q breakpoint region. The genes studied were the two putative oncogenes INT1 and GLI, and the collagen type II alpha 1 gene, COL2A1. No rearrangement or amplification could be detected for any of the three gene sequences.

We have cytogenetically investigated short-term cultures from an angioleiomyoma. Monosomy for chromosome 13, and one to two small markers were observed in the tumor cells, resulting in the karyotype 46-47,XY,-13,+1-2 mar.

Cytogenetic analysis of short-term cultures from two uterine leiomyomas revealed, in addition to the primary abnormality, the reciprocal translocation t(12;14)(q14-15;q23-24), secondary structural changes that in both cases included ring chromosomes and rearrangements of chromosome 1. One tumor had the karyotype 46,XX,r(1)(p34q32),ins(8;9)(q13;q13q22),t(12;14)(q14-15;q23- 24). Massive numerical rearrangements were found in the second leiomyoma, with chromosome numbers ranging from 47 to 92. In spite of this variability, two main cell populations could be discerned, one near-diploid, the other hypotetraploid, with most mitoses having chromosome numbers between 80 and 88. These findings were corroborated by flow cytometry, which revealed two peaks corresponding to DNA indexes of 0.97 and 1.77. The structural abnormalities t(1;1)(p31;q44) and t(12;14)(q14-15;q23-24) were present in all karyotypically abnormal cells, and one or more unidentified ring chromosomes were observed in most of the hypotetraploid mitoses. In no cells were double copies of the t(1;1) and t(12;14) rearrangements detected. The similarity between the secondary changes in the cases reported here suggests that clonal evolution in uterine leiomyoma is nonrandom.