Chromosomal anomalies in prostatic intraepithelial neoplasia and carcinoma detected by fluorescence in situ hybridization.

The pathogenetic relationship between high-grade prostatic intraepithelial neoplasia (PIN), prostatic carcinoma, and metastases is poorly understood. We used fluorescence in situ hybridization (FISH) with centromere-specific probes for chromosomes 7, 8, 10, 12, and Y to evaluate numeric chromosomal anomalies in PIN (68 foci), localized prostatic carcinoma (78 foci), and lymph node metastases (8 foci) in 40 whole-mount radical prostatectomy and pelvic lymphadenectomy specimens. Chromosomal anomalies were found in 50, 51, and 100% of the foci of PIN, carcinoma, and metastases, respectively. The mean numbers of abnormal chromosomes per focus were 0.66 in PIN, 1.09 in carcinoma, and 3.75 in metastases. The most frequent anomaly in PIN was a gain of chromosome 8 (32% of foci), followed by gains of chromosomes 10 (13%), 7 (10%), 12 (4%), and Y (4%). The most frequent anomalies in foci of carcinoma were gains of chromosomes 7 and 8 (28% and 30% of foci, respectively), followed by gains of chromosomes 10 (23%), 12 (9%), and Y (9%). There was a positive correlation of the gain of chromosome 8 with the pathological stage and Gleason score (both P < 0.05). Usually, carcinoma foci contained more anomalies than paired PIN foci, but five prostates contained one or more foci of PIN with more anomalies than carcinoma. Among the cases with metastases, usually one or more foci of the primary tumor shared chromosomal anomalies with the matched metastases. Our results indicate that PIN and prostatic carcinoma foci have similar proportions of chromosomal anomalies, but foci of carcinoma usually have more alterations. This observation supports the hypothesis that PIN is often a precursor of carcinoma, although there are some carcinoma foci that have few or no apparent chromosomal alterations, whereas concurrent PIN foci have multiple alterations. A gain of chromosome 8 was the most common numerical alteration and was associated with increasing cancer stage and grade, suggesting that it may play a role in the initiation and progression of prostatic carcinoma. Usually, one or more foci of the primary tumor shared chromosomal anomalies with associated lymph node metastases, suggesting that, often, just a single focus of carcinoma gives rise to metastases.

Aneuploidy and aneusomy of chromosome 7 detected by fluorescence in situ hybridization are markers of poor prognosis in prostate cancer.

Fluorescence in situ hybridization is a new methodology which can be used to detect cytogenetic anomalies within interphase tumor cells. We used this technique to identify nonrandom numeric chromosomal alterations in tumor specimens from the poorest prognosis patients with pathological stages T2N0M0 and T3N0M0 prostate carcinomas. Among 1368 patients treated by radical prostatectomy, 25 study patients were ascertained who died most quickly from progressive prostate carcinoma within 3 years of diagnosis and surgery. Tumors from 25 control patients who survival for more than 5 years and who were matched for age, tumor histological grade, and pathological stage also were evaluated. The tumors from all 25 (100%) poor prognosis patients and from 11 of 25 (44%) control patients were found to be aneuploid by fluorescence in situ hybridization (P < 0.0001). Alterations of chromosome 7 were observed in 24 of the tumors (96%) from the poor prognosis patients versus 3 tumors (12%) from the control group (P < 0.0001). Moreover, a characteristic aneuploidy pattern with multiple abnormal chromosomes and a hypertetrasomic population was generally found in tumors from the poor prognosis patients. This preliminary study suggests that fluorescence in situ hybridization studies of prostate cancer specimens may help to identify those patients at highest risk for early cancer death.

Aneusomies of chromosomes 8 and Y detected by fluorescence in situ hybridization are prognostic markers for pathological stage C (pt3N0M0) prostate carcinoma.

In an attempt to identify new prognostic markers, we performed fluorescence in situ hybridization (FISH) ploidy analysis of tumor tissue from patients with a targeted stage and histological grade of prostate carcinoma. We identified all 227 patients from the Mayo Clinic radical prostatectomy data base who had a high histological grade pathological stage C (pT3N0M0) tumor removed between 1966 and 1987. After histological review of the paraffin-embedded specimen blocks, 181 cases were suitable for FISH analysis using chromosome enumeration probes for chromosomes 7, 8, 10, 12, X, and Y. FISH detected 80 (44%) diploid, 22 (12%) tetraploid, and 79 (44%) aneuploid tumors. The common aneusomies were of chromosomes 7 and 8, which were present in 51 (28%) and 46 (25%) tumors, respectively. Aneusomies of chromosomes 10, 12, X, and Y were observed in 11 (6%), 15 (8%) 12 (7%) and 16 (9%) tumors, respectively. FISH aneuploid tumors showed a trend of more frequent systemic prostate cancer progression than nonaneuploid tumors (P = 0.060). For individual chromosome anomalies, gains of chromosome 8, aneusomy of chromosome 8, and aneusomy of chromosome Y correlated highly with systemic cancer progression (P = 0.006, 0.013, and 0.021, respectively). Gains of chromosome Y and aneusomy of chromosome Y were associated with an increased prostate cancer death rate (P < 0.001 for both). Multivariate analysis showed that gains of chromosome 8 and aneusomy of chromosome Y were significant independent "predictors" of systemic cancer progression (P = 0.008) and cancer death (P < 0.001), respectively. These results demonstrate that aneuploidy and specific aneusomies detected by FISH are potential markers for a poor prognosis in histological high-grade pathological stage C (pT3N0M0) prostate carcinoma.

Correlation of cytogenetic and fluorescence in situ hybridization (FISH) studies in normal and gliotic brain.

In vitro tissue culturing, for karyotype analysis, may introduce artifacts confounding the cytogenetic evaluation of tissues with low baseline proliferative activity. Utilizing a panel of fluorescence in situ hybridization (FISH) probes for chromosomes 7, 8, 9, 10, 12, 17, 18, X, and Y, we compared the results of FISH analysis of non-tumorous normal (11 patients) and gliotic (10 patients) brain tissue touch preparations with those of cytogenetic evaluation performed on short-term primary cultures of the same material. We found a significant rate of apparent monosomy of chromosomes 8 and 17 by FISH analysis, with no corresponding clonal chromosomal loss detected by karyotype evaluation. These monosomy rates were significantly lower in gliotic than in normal brain tissue, and image analysis suggested that this apparent monosomy was due to interphase pairing of homologous centromere signals. Two distinct Y-chromosome signals were seen in 9.4% of nuclei by FISH, with 3 of 15 males displaying disomy Y rates over 15%. Disomy Y rates correlated approximately with age and clonal disomy Y was seen in the karyotype of one of these specimens. Karyotype analysis demonstrated loss of a sex chromosome in 6 specimens, while no sex chromosome nullisomy was detected by FISH. FISH is a valuable adjunct to the cytogenetic evaluation of tissues with low baseline proliferative activity. The differences in relative monosomy rates between normal and gliotic brain suggest that alterations in nuclear architecture and/or DNA sequence accompany the transition from normal to reactive glia.

Fluorescence in situ hybridization analysis of trisomy 12 in ovarian tumors.

Conventional cytogenetic studies have suggested that trisomy 12 may be a characteristic nonrandom numerical chromosome anomaly in benign ovarian tumors, particularly sex cord-stromal tumors. To confirm this finding, and to avoid possible culture artifact introduced during cytogenetic analysis, the authors performed fluorescence in situ hybridization (FISH) in paraffin-embedded samples of select ovarian neoplasms. Forty-four ovarian fibromas and granulosa cell tumors and 31 benign and borderline epithelial ovarian tumors were examined for the presence of trisomy 12. Trisomy 12 was detected in 40% (8 of 20) of the fibromas. No evidence of trisomy 12 was present in 24 granulosa cell tumors, although 1 granulosa cell tumor was tetrasomic for chromosome 12. Trisomy 12 was found in 27% (3 of 11) of the serous borderline tumors, but was not observed in any of the benign epithelial tumors (13 serous and 7 mucinous cystadenomas). These results confirm that trisomy 12 occurs in a significant proportion of fibromas. However, the incidence of trisomy 12 in granulosa cell tumors is far lower than suggested by previous studies. These results, in conjunction with those of previous cytogenetic reports, suggest that trisomy 12 is rare in benign epithelial ovarian tumors, but occurs fairly commonly as a sole anomaly in borderline epithelial tumors. Further investigation is necessary to establish the significance of trisomy 12 in the pathogenesis of these tumors.

Detection of trisomy 12 by FISH in untreated B-chronic lymphocytic leukemia: correlation with stage and CD20 antigen expression intensity.

We studied cells from 30 controls and 85 cases of untreated B-chronic lymphocytic leukemia (CLL) with a fluorescence in-situ hybridization (FISH) technique utilizing a probe to chromosome 12. By use of a threshold of > 2% for trisomy 12 for the CLL cases (the mean +3 SD for controls was 1.3%), 20% (17/85) were trisomy 12. The mean % cells positive was 32.6 (median, 39.4; range, 2.4-79.1). There was a trend toward an higher incidence of trisomy 12 in patients with Rai stages 1-4 vs Rai 0 (p = 0.16). Forty-seven % (8/17) of patients with trisomy 12 had strong intensity CD20 antigen expression compared to 21% (14/68) of patients without trisomy 12 (p = 0.03). Trisomy 12 associated with CLL is easily detected by FISH with an overall incidence of 20%. This technique should be applied to larger groups of patients to confirm the potential variation among Rai stages and immunophenotypic subgroups.

Use of fluorescence in situ hybridization to detect loss of chromosome 10 in astrocytomas.

Models describing progression in the genetic derangement of glial tumors have shown loss of chromosome 10 to occur most frequently in high-grade lesions, suggesting that identification of this loss may be prognostically significant. Fluorescence in situ hybridization (FISH) analysis may be a valuable adjunct to histological grading if it can accurately detect this loss. In this paper, the authors correlate results obtained from FISH, cytogenetic, molecular genetic, and flow cytometric analyses of a series of 39 brain specimens, including seven normal, two gliotic, and 30 neoplastic (one Grade II, one Grade III, and 28 Grade IV astrocytoma) specimens. Contiguous section of freshly resected surgical tissue were submitted for tissue culturing (karyotype) and touch preparation (FISH), snap-frozen (molecular genetic), or paraffin-embedded (histology and flow cytometry). Centromere-specific probes for chromosomes 10 and 12 were used for FISH analysis, and 19 restriction fragment length polymorphisms (two p-arm and 17 q-arm) and four microsatellite sequence polymorphisms (three p-arm and one q-arm) were used for molecular genetic analysis of chromosome 10. Findings showed FISH and loss of heterozygosity (LOH) analyses to be concordant in 33 of 38 specimens (sensitivity 94%, specificity 81%), with one specimen indeterminate on LOH analysis. Both FISH and LOH analyses were more sensitive at detecting chromosome 10 loss than conventional cytogenetic (karyotype) analysis. The authors conclude that FISH is a sensitive test for detecting chromosome 10 loss and ploidy in astrocytic tumors.

Frequent occurrence of cytogenetic abnormalities in sporadic nonmedullary thyroid carcinoma.

Cytogenetic studies may provide important clues to the molecular pathogenesis of thyroid neoplasia. Thus, the authors attempted cytogenetic studies on 12 thyroid carcinomas: seven papillary, three follicular, and two anaplastic. Successful cytogenetic results were obtained on all 12 tumors; nine (75%) had one or more chromosomally abnormal clones. Four of the papillary carcinomas had a simple clonal karyotype, and three had no apparent chromosome abnormality. All four abnormal papillary tumors contained an anomaly of a chromosome 10q arm. In one instance, an inv(10)(q11.2q21.2) was observed in a Grade 2 papillary carcinoma as the sole acquired abnormality. In another case, an inversion or insertion involving 10q21.2 was found in a Grade 1 papillary tumor. The karyotype of a third tumor, a Grade 1 papillary carcinoma, was 46,XX,der(5)t(5;10)(p15.3;q11),der(9)t(9;?)(q11;?). A fourth abnormal papillary carcinoma, a Grade 1 tumor, had a t(6;10)(q21;q26.1) as the sole abnormality. Each of the five follicular or anaplastic carcinomas had a complex clonal karyotype. The three follicular carcinomas contained an abnormality of 3p25-p21, along with several other chromosome abnormalities.

Interphase molecular cytogenetic analysis of epithelial ovarian carcinomas.

Karyotype information on ovarian carcinomas has been limited because the tumors are often difficult to culture and the resultant metaphases can have complex numerical and structural chromosomal anomalies. Fluorescent in situ hybridization is a rapid method of determining centromere copy number in metaphase cells and interphase nuclei. Fluorescent in situ hybridization was used to determine the numerical centromere complement of chromosomes X, 8, 12, and 17 and HER-2/neu gene amplification within interphase nuclei of 25 primary epithelial ovarian carcinomas. Touch preparations of the carcinomas were hybridized with two-color combinations of directly labeled alpha-satellite centromeric chromosome enumeration probes and a directly labeled HER-2/neu probe. Modal centromere copy numbers for each of the four chromosomes were used to determine numerical abnormalities relative to the flow cytometric DNA ploidy level for each tumor. Four cases were found to be normal with respect to the four chromosomes studied. In the remaining 21 cases a relative loss of chromosomes 17 (16 cases) and X (nine cases) and a relative gain of chromosomes 12 (10 cases) and 8 (nine cases) were the most common findings. In addition, the HER-2/neu gene was amplified in two of the 25 tumors. In conclusion, fluorescent in situ hybridization is an excellent method for rapid determination of numerical abnormalities and gene amplification in ovarian carcinomas.