Two subclones in a case of uveal melanoma. Relevance of monosomy 3 and multiplication of chromosome 8q

Uveal Melanoma Metastasis

Uveal melanoma (UM) is characterized by relatively few, highly incident molecular alterations and their association with metastatic risk is deeply understood. Nevertheless, this knowledge has so far not led to innovative therapies for the successful treatment of UM metastases or for adjuvant therapy, leaving survival after diagnosis of metastatic UM almost unaltered in decades. The driver mutations of UM, mainly in the G-protein genes GNAQ and GNA11, activate the MAP-kinase pathway as well as the YAP/TAZ pathway. At present, there are no drugs that target the latter and this likely explains the failure of mitogen activated kinase kinase inhibitors. Immune checkpoint blockers, despite the game changing effect in cutaneous melanoma (CM), show only limited effects in UM probably because of the low mutational burden of 0.5 per megabase and the unavailability of antibodies targeting the main immune checkpoint active in UM. The highly pro-tumorigenic microenvironment of UM also contributes to therapy resistance. However, T-cell redirection by a soluble T-cell receptor that is fused to an anti-CD3 single-chain variable fragment, local, liver specific therapy, new immune checkpoint blockers, and YAP/TAZ specific drugs give new hope to repeating the success of innovative therapy obtained for CM.

Role of somatic mutations and chromosomal aberrations in the prognosis of uveal melanoma in a Spanish patient cohort

BACKGROUND

Uveal melanoma (UM) has a high tendency to cause liver metastases. Metastatic disease is fatal, with a low survival rate. There are two large groups of UMs that, according to their risk of metastatic disease, can be divided into risk subgroups based on histopathological, cytogenetic and molecular characteristics. The presence of somatic mutations in certain genes may explain the origin and prognosis of these tumours.

METHODS

Forty-six UM samples previously classified as high or low metastatic risk according to chromosome 3 copy number status were tested for somatic mutations. A multi-gene targeting strategy was adopted, and sequencing was performed using AmpliSeq technology.

RESULTS

Mutations were found in all major UM-related genes. BAP1 mutations confer an increased risk of metastases in high-risk tumours; thus, this gene acts as a strong prognostic predictor in UM. The presence of somatic mutations in LZTS1 did not show significant differences in the risk of metastases.

CONCLUSIONS

This result supports the idea that exploring mutations and copy number variations in UM provides insights into patient outcomes. Genetic tests allow the determination of accurate personalized molecular profiles with a fundamental prognostic purpose.

Scientific and clinical implications of genetic and cellular heterogeneity in uveal melanoma

Here, we discuss the presence and roles of heterogeneity in the development of uveal melanoma. Both genetic and cellular heterogeneity are considered, as their presence became undeniable due to single cell approaches that have recently been used in uveal melanoma analysis. However, the presence of precursor clones and immune infiltrate in uveal melanoma have been described as being part of the tumour already decades ago. Since uveal melanoma grow in the corpus vitreous, they present a unique tumour model because every cell present in the tumour tissue is actually part of the tumour and possibly plays a role. For an effective treatment of uveal melanoma metastasis, it should be clear whether precursor clones and normal cells play an active role in progression and metastasis. We propagate analysis of bulk tissue that allows analysis of tumour heterogeneity in a clinical setting.

[New molecular pathological strategies for malignant iris tumors]

BACKGROUND

Molecular pathological research offers new chances for the diagnostic and therapeutic management of malignant iris tumors. Besides immunohistological and polymerase chain reaction analyses further techniques, such as multiplex ligation-dependent probe amplification, microsatellite analyses and next-generation sequencing are able to detect various mutations in the tumor genome.

OBJECTIVE

An up to date review of new molecular pathological strategies for malignant iris tumors was carried out.

METHODS

This article provides a review of the recent literature based on a PubMed search and clinical experience with iris tumors.

RESULTS

The diagnostic characteristics and targeted treatment options are presented, exemplified by iris melanoma and iris carcinoma metastases. In iris melanomas, mutations in the GNA11 and GNAQ genes (in approximately 85% of the cases) seem to be important. Furthermore, the monosomy-3 status should be investigated in these tumors. In iris lymphomas, molecular pathological analyses are essential for an exact diagnosis. Detection of mutations in MYD88, BRAF, KLF2, ID3, TCF3, STAT3, RHo, TET2, IDH2, CXCR4, CD79B and DNMT3A are helpful. In particular, the detection of the CD20 antigen is of therapeutic relevance because this lymphoma subgroup responds well to rituximab, a CD20 antibody treatment. In iris carcinoma metastases, investigations for mutations are helpful because then a targeted treatment seems to be possible.

CONCLUSION

Molecular pathological analyses will become essential in the future management of iris tumors because they play a key role towards a personalized treatment approach.

Genetic and epigenetic insights into uveal melanoma

Uveal melanoma (UM) is the most frequent primary intraocular tumor in Caucasian adults and is potentially fatal if metastases develop. While several prognostic genetic changes have been identified in UM, epigenetic influences are now getting closer attention. Recent technological advances have allowed to exam the human genome to a greater extent and have improved our understanding of several diseases including malignant tumors. In this context, there has been tremendous progress in the field of UM pathogenesis. Herein, we review the literature with emphasis on genetic alterations, epigenetic modifications and signaling pathways as well as possible biomarkers in UM. In addition, different research models for UM are discussed. New insights and major challenges are outlined in order to evaluate the current status for this potentially devastating disease.

Uveal melanoma

Uveal melanoma is the most common primary intraocular malignancy in adults. It is associated with a high rate of distant tumor spread and consequent mortality. Unlike retinoblastoma, for which treatment advances over the last few decades have resulted in a dramatic improvement in survival, outcomes for patients with uveal melanoma remain unchanged. Despite improvement in local control of this tumor, roughly 50% of patients develop metastatic disease within 15 years. Delays in diagnosis and marked vascularity of this tumor may underlie that situation. Tumor size, location, histopathologic appearance, cytogenetic abnormalities, and molecular profiling are used in prognostication. The revised 7th edition of the American Joint Committee on Cancer (AJCC) manual has presented new information that may improve that process as well. Herein, we review current knowledge on uveal melanoma.

Risk factors associated with secondary enucleation after fractionated stereotactic radiotherapy in uveal melanoma

PURPOSE

To evaluate risk factors for secondary enucleation after fractionated stereotactic radiotherapy (fSRT) in uveal melanoma.

METHODS

In this retrospective study, clinical data of 118 consecutive patients who had initially been treated with fSRT between 1999 and 2009 were collected and analysed. The patients who had undergone secondary enucleation were identified and examined for clinical, histopathological and cytogenetical (fluorescence in situ hybridization determined) data. Also, the reasons for secondary enucleation, such as treatment failure (progressive tumour growth or tumour recurrence) or complications following fSRT (painful blind eye), were recorded and examined.

RESULTS

The secondary enucleation rate was 16% after a median follow-up of 4.7 years, with 5% due to treatment failure and 11% due to complications. In the univariate analysis, large tumour diameter (p = 0.019) and large tumour height (p = 0.001) were associated with secondary enucleation, tumour involvement of the optic disc showed borderline significance (p = 0.068). Cox regression multivariate analysis displayed large tumour height as independent prognostic factor (HR 1.42, 95% CI 1.12-1.81, p = 0.004). Following secondary enucleation, mitotic figures were present in five of 18 tumours, and gain of chromosome 8q was also present in five tumours. Within the subgroup of patients who required secondary enucleation due to failed tumour control by fSRT (N = 6), mitotic figures were present in four of six tumours while gain of 8q was present in three of six tumours.

CONCLUSION

Secondary enucleation after previous fSRT was associated with large tumour height. High mitotic counts and gain of chromosome 8q were frequently found in secondary enucleations and possibly indicate a more aggressive or radiation-resistant tumour.

Digital PCR validates 8q dosage as prognostic tool in uveal melanoma

Background

Uveal melanoma (UM) development and progression is correlated with specific molecular changes. Recurrent mutations in GNAQ and GNA11 initiate UM development while tumour progression is correlated with monosomy of chromosome 3 and gain of chromosome 8q. Hence, molecular analysis of UM is useful for diagnosis and prognosis. The aim of this study is to evaluate the use of digital PCR (dPCR) for molecular analysis of UM.

Methods

A series of 66 UM was analysed with dPCR for three hotspot mutations in GNAQ/GNA11 with mutation specific probes. The status of chromosomes 3 and 8 were analysed with genomic probes. The results of dPCR analysis were cross-validated with Sanger sequencing, SNP array analysis, and karyotyping.

Results

Using dPCR, we were able to reconstitute the molecular profile of 66 enucleated UM. With digital PCR, GNAQ/GNA11 mutations were detected in 60 of the 66 UM. Sanger sequencing revealed three rare variants, and, combined, these assays revealed GNAQ/GNA11 mutations in 95% of UM. Monosomy 3 was present in 43 and chromosome 8 aberrations in 52 of the 66 UM. Survival analysis showed that increasing 8q copy numbers were positively correlated with metastasis risk.

Conclusion

Molecular analysis with dPCR is fast and sensitive. Just like the recurrent genomic aberrations of chromosome 3 and 8, hotspot mutations in GNAQ and GNA11 are effectively detected in heterogeneous samples. Increased sensitivity contributes to the number of mutations and chromosomal aberrations detected. Moreover, quantification of copy number with dPCR validated 8q dosage as a sensitive prognostic tool in UM, of which implementation in disease prediction models will further improve prognostication.

Case report: an atypical peripapillary uveal melanoma

Background

The treatment of uveal melanoma has seen a shift towards eye conserving treatments. Efforts have been made towards the identification of patients at high risk of metastatic disease with the use of prognostic fine needle biopsy, Monosomy 3 a risk factor for metastatic death thought to occur early in the development of uveal melanoma.

Case presentation

We report a case in which an atypical optic nerve lesion was found to be a peripapillary primary uveal melanoma with distinct non-pigmented and pigmented halves on gross dissection and corresponding disomy 3 and monosomy 3 halves. The tumour demonstrated rapid growth with apparent transformation from disomy 3 to monosomy 3.

Conclusions

These are clinical features that challenge the current concepts of the cytogenetic pathogenesis of uveal melanoma and demonstrate the potential problems and limitations of prognostic fine needle biopsy and molecular classifications.

Evidence of epidermal growth factor receptor expression in uveal melanoma: inhibition of epidermal growth factor-mediated signalling by Gefitinib and Cetuximab triggered antibody-dependent cellular cytotoxicity

Despite advances in surgery and radiotherapy of uveal melanoma (UM), many patients develop distant metastases that poorly respond to therapy. Improved therapies for the metastatic disease are therefore urgently needed. Expression of the epidermal growth factor receptor (EGFR), a target of kinase inhibitors and humanised antibodies in use for several cancers, had been reported. Forty-eight human UMs were analysed by expression profiling. Signalling was tested in three EGFR expressing UM cell lines by Western blotting using phosphorylation specific antibodies for EGFR and the downstream mediators AKT (v-akt murine thymoma viral oncogene homolog) and extracellular signal-regulated kinase (ERK). Evidence for signalling in tumours was obtained through the application of a UM-specific EGF-signature. The EGFR specific kinase inhibitor, Gefitinib and the humanised monoclonal antibody, Cetuximab, were tested for their effect on EGFR signalling. Natural killer cell mediated antibody-dependent cellular cytotoxicity (ADCC) and tumour necrosis factor α (TNF-α) release was analysed for Cetuximab. Fourteen of 48 UMs and three of 14 cell lines (over-)express EGFR, at least in part due to trisomy of the EGFR locus on chromosome 7p12. EGFR and the downstream mediator, AKT, are phosphorylated upon stimulation with EGF in EGFR expressing cell lines. EGFR over-expressing tumours but not EGFR negative tumours show an activated EGF-signature. Gefitinib inhibits EGFR and AKT phosphorylation and Cetuximab induces EGFR phosphorylation but inhibits signalling to AKT induced with EGF. Cetuximab triggers natural killer (NK) cells to lyse EGFR+ cell lines and to release TNF-α. EGFR appears suited as a novel molecular drug target for therapy of uveal melanoma.

Molecular pathology of uveal melanoma

Like other cancers, uveal melanomas (UM) are characterised by an uncontrolled, clonal, cellular proliferation, occurring as a result of numerous genetic, and epigenetic aberrations. Signalling pathways known to be disrupted in UM include: (1) the retinoblastoma pathway, probably as a result of cyclin D1 overexpression; p53 signalling, possibly as a consequence of MDM2 overexpression; and the P13K/AKT and mitogen-activated protein kinase/extracellular signal-related kinase pathway pathways that are disturbed as a result of PTEN and GNAQ/11 mutations, respectively. Characteristic chromosomal abnormalities are common and include 6p gain, associated with a good prognosis, as well as 1p loss, 3 loss, and 8q gain, which correlate with high mortality. These are identified by techniques such as fluorescence in situ hybridisation, comparative genomic hybridisation, microsatellite analysis, multiplex ligation-dependent probe amplification, and single-nucleotide polymorphisms. UM can also be categorised by their gene expression profiles as class 1 or class 2, the latter correlating with poor survival, as do BRCA1-associated protein-1 (BAP1) inactivating mutations. Genetic testing of UM has enhanced prognostication, especially when results are integrated with histological and clinical data. The identification of abnormal signalling pathways, genes and proteins in UM opens the way for target-based therapies, improving prospects for conserving vision and prolonging life.

Choroidal melanoma

Choroidal melanoma is the most common primary intra-ocular malignant tumor and second most common site of ten malignant melanoma sites in the body. Current diagnosis of choroidal melanoma is based on both the clinical experience of the specialist and modern diagnostic techniques such as indirect ophthalmoscopy, A- and B-ultrasonography scans, fundus fluorescein angiography, and transillumination. Invasive studies such as fine needle aspiration cytology can have significant morbidity and should only be considered if therapeutic intervention is indicated and diagnosis cannot be established by any other means. Several modes of treatment are available for choroidal melanoma. Multiple factors are taken into account when deciding one approach over other approaches, such as visual acuity of the affected eye, visual acuity of the contralateral eye, tumor size, location, ocular structures involved and presence of metastases. A comprehensive review of literature available in books and indexed journals was done. This article discusses in detail epidemiology, diagnosis, current available treatment options, and prognosis and survival of choroidal melanoma.

Cytogenetics and prognosis for uveal melanoma in Korean patients

PURPOSE

To determine the rate of mortality for uveal melanoma in the Korean population and assess whether it correlates with cytogenetic data, and clinical and histopathological factors.

METHODS

A retrospective review of medical files from 33 uveal melanoma patients who underwent enucleation at Yonsei University, Seoul, Korea, between January, 1994 and December, 2009 was performed. Dual-colour fluorescence in situ hybridization was performed using centromeric probes for chromosome 3 and 8 in archived patient tissues.

RESULTS

The mean age of patients was 53.2 years (range; 29-78), and the mean largest basal diameter was 11.8 mm (range; 6.0-18.1). Of the 20 tissue blocks with available cytogenetic data, there was monosomy 3 in seven (35%) and polysomy 8 in four (20%). The presence of monosomy 3 (p < 0.001), polysomy 8 (p < 0.001), ciliary body involvement (p < 0.001), a mitotic rate ≥5/40 high-power fields (p = 0.006), closed extravascular matrix loop (p = 0.025), large basal tumour diameter (p = 0.029) and epithelioid cellularity (p = 0.038) predicted melanoma-related mortality. The median time from enucleation to liver metastasis was 16 months (range; 10-70), and the median survival after metastasis was 5 months (range; 1-9). The Kaplan--Meier survival curve estimated the metastatic death rate to be 22% for 5 years and 30% for 10 years.

CONCLUSIONS

Korean patients with uveal melanoma are younger and appear to exhibit no worse prognosis than Caucasian. Cytogenetic abnormality of chromosome 3 and 8 highly predicted metastatic death.

Phase I trial combining gemcitabine and treosulfan in advanced cutaneous and uveal melanoma patients

Gemcitabine and treosulfan are DNA-damaging agents. Preclinical studies suggest that synergism exists when melanoma cells are exposed to both drugs concurrently. We conducted a phase I trial in advanced melanoma patients to determine the optimal dose of gemcitabine to be combined with treosulfan. Cohorts of three patients received increasing doses of gemcitabine, commencing at 0.5 g m⁻², followed by a fixed dose of 5.0 g m⁻² treosulfan on day one of a 21-day cycle. Patients alternately received a first cycle of single-agent gemcitabine or treosulfan before subsequent cycles of both drugs. Peripheral blood lymphocytes were collected in cycles 1 and 2 at various time points until 48 h post-treatment. The single-cell gel electrophoresis (Comet) assay was used to measure chemotherapy-induced DNA damage. A total of 27 patients were enrolled, no objective responses were observed, but two uveal melanoma patients had minor responses. Dose-limiting myelosuppression was reached at 3.0 g m⁻² gemcitabine. DNA single-strand breaks were detected 4 h post-gemcitabine, repaired by 24 h. DNA interstrand crosslinks were detected 4 h post-treosulfan, fully removed by 48 h. Following combination chemotherapy, treosulfan-induced DNA crosslinks persisted, still being detectable 48 h post-treatment, supporting the hypothesis that gemcitabine potentiates treosulfan-induced cytotoxicity. The recommended regimen for further study is 2.5 g m⁻² gemcitabine combined with 5.0 g m⁻² treosulfan.

Données cytogénétiques actuelles : vers la monosomie du chromosme 3 comme principal facteur pronostique du mélanome uvéal

Uveal melanoma is the most frequent intraocular cancer. The recent development of new technologies such as microsatellite analysis and comparative genomic hybridization have elucidated both the cytogenetics and the natural history of this disease. Fifty to 60% of uveal melanomas are linked to monosomy 3, which appears as an early and determinant event in tumor progression. Tumors with this anomaly have a very poor prognosis. Recent work suggests that this category of uveal melanomas represents a distinct pathological entity from that associated with normal disomy 3. Chromosome 6 aberrations probably make up a second entry point into the process of carcinogenesis, while gains in 8q seem to appear later in the natural history of uveal melanoma because of their higher frequency in larger tumors. Progress in genome analysis has identified regions in chromosomes 3, 6, and 8 as those most probably involved in tumorigenesis. It is to be hoped that this will soon lead to the discovery of the genes responsible.

Relation between DNA ploidy status and the expression of the DNA-mismatch repair genes MLH1 and MSH2 in cytological specimens of melanoma lymph node and liver metastases

DNA-mismatch repair is essential for preventing genetic instability, and its important protective role has been demonstrated in several tumors. The main aim of this study was to investigate the expression of MLH1 and MSH2 (on the RNA level) in melanoma liver and lymph node metastases, and to define the relation between DNA ploidy status and mismatch repair gene expression. MLH1 was found in 29/33 melanoma lymph node and in 5/17 melanoma liver metastases. MSH2 was present in 26/33 lymph node and 5/17 liver metastases. A comparison of MLH1 and MSH2 positive and negative melanoma metastases showed that there were highly significant differences in the percentages of diploid cells, aneuploid cells between 4c and 8c, octaploid cells, and 5c exceeding rate. This fact confirms the strong relation between the loss of DNA-mismatch repair gene expression and advanced DNA aneuploidy status in melanoma metastases.

Identification of chromosomes 3, 6, and 8 aberrations in uveal melanoma by microsatellite analysis in comparison to comparative genomic hybridization

In uveal melanoma, monosomy 3 is strongly associated with metastic disease and poor prognosis. Cytogenetic analysis and comparative genomic hybridization (CGH) have been used to identify chromosomal aberrations in uveal melanoma. As these methods are costly and time consuming in routine diagnostic settings, we evaluated whether tumors with monosomy 3 can be reliably identified by microsatellite analysis (MSA). In addition, we also tested if aberrations of chromosomes 6 and 8, which have also been associated with the course of the disease, can be detected by MSA. We established a protocol for MSA of 23 markers, 3-4 on each arm of chromosomes 3, 6, and 8. Twenty tumors were analyzed by CGH and MSA, and 10 tumors were analyzed by MSA only. For chromosome 3, the results of CGH and MSA were concordant, thus indicating that the dosage of this chromosome can reliably be determined by MSA. However, MSA failed to detect copy number gains at 6p in some tumors. Moreover, despite quantitative evaluation of allele ratios, it was not possible to discern 8p losses and gains reliably. We thus conclude that while MSA can be used to determine monosomy 3 in uveal melanoma, careful interpretation of results for chromosomes 6 and 8 is recommended.

Individuals with presumably hereditary uveal melanoma do not harbour germline mutations in the coding regions of either the P16INK4A, P14ARF or cdk4 genes

In familial cutaneous malignant melanoma (CMM), disruption of the retinoblastoma (pRB) pathway frequently occurs through inactivating mutations in the p16 (p16INK4A/CDKN2A/MTS1) gene or activating mutations in the G1-specific cyclin dependent kinase 4 gene (CDK4). Uveal malignant melanoma (UMM) also occurs in a familial setting, or sometimes in association with familial or sporadic CMM. Molecular studies of sporadic UMM have revealed somatic deletions covering the INK4A-ARF locus (encoding P16INK4A and P14ARF) in a large proportion of tumours. We hypothesized that germline mutations in the p16INK4A, p14ARF or CDK4 genes might contribute to some cases of familial UMM, or to some cases of UMM associated with another melanoma. Out of 155 patients treated at the Institut Curie for UMM between 1994 and 1997, and interviewed about their personal and familial history of melanoma, we identified seven patients with a relative affected with UMM (n = 6) or CMM (n = 1), and two patients who have had, in addition to UMM, a personal history of second melanoma, UMM (n = 1), or CMM (n = 1). We screened by polymerase chain reaction single-strand conformation polymorphism the entire coding sequence of the INK4A-ARF locus (exon 1alpha from p16INK4A, exon 1beta from p14ARF, and exons 2 and 3, common to both genes), as well as the exons 2, 5 and 8 of the CDK4 gene, coding for the functional domains involved in p16 and/or cyclin D1 binding. A previously reported polymorphism in exon 3 of the INK4A-ARF locus was found in one patient affected with bilateral UMM, but no germline mutations were detected, either in the p16INK4A, p14ARF or CDK4 genes. Our data support the involvement of other genes in predisposition to uveal melanoma.

Association of specific chromosome alterations with tumour phenotype in posterior uveal melanoma

Posterior uveal melanomas have recurrent alterations of chromosomes 1, 3, 6 and 8. In particular, changes of chromosomes 3 and 8 occur in association, appear to characterize those tumours with a ciliary body component, and have been shown to be of prognostic significance. The relevance of other chromosome alterations is less certain. We have performed cytogenetic analysis on 42 previously untreated primary posterior uveal melanomas. Of interest was the observation that as tumour size increased the involvement of specific chromosome changes, and the amount of chromosome abnormalities likewise increased. Loss, or partial deletions, of the short arm of chromosome 1 were found to associate with larger ciliary body melanomas; typically, loss of the short arm resulted from unbalanced translocations, the partners of which varied. Trisomy of chromosome 21 occurred more often in ciliary body melanomas, whilst rearrangements of chromosomes 6 and 11 were primarily related to choroidal melanomas. Our results imply that alterations of chromosome 1 are important in the progression of some uveal melanomas, and that other chromosome abnormalities, besides those of chromosomes 3 and 8, are associated with ocular tumours of particular locations.

Clinical applications of chromosome analysis, from fine needle aspiration biopsies, of posterior uveal melanomas

PURPOSE

An accurate assessment of prognosis is essential to the clinical assessment of malignancy. In posterior uveal melanoma specific chromosome alterations have been shown to correlate significantly with prognosis; but the procedure is restricted to patients treated surgically, and in consequence has been limited mainly to large tumours. Fine needle aspiration biopsy (FNAB) may provide sufficient material to perform this technique, and allow its use in the in situ assessment of tumours, including small lesions. To determine the feasibility of this approach we have conducted a pilot study using enucleated tumours.

METHODS

Ten cases of posterior uveal melanoma were studied. In each instance both a test FNAB and a standard tissue preparation were conducted, and the results compared. FNABS were obtained from enucleated tumours by aspirating cells using a 5 ml syringe with a .25 gauge needle; cells were injected into phosphate-buffered saline, spun down and established in vitro. Conventional short-term cultures were established from tumour tissue samples, which were minced prior to the establishment of cultures. Cytogenetic analysis was performed following standard protocols.

RESULTS

Of the 10 cases examined, full chromosome analysis was obtainable from all standard tissue short-term cultures. Cytogenetics was successful from cultures of 6 FNAB, with 2 further FNAB producing partial analyses. No major clonal differences were determined between the two procedures.

CONCLUSIONS

Cytogenetic analysis of FNAB appears to be entirely feasible for posterior uveal melanomas, and may permit an accurate in situ assessment of tumours, including small lesions.

Assessment of chromosome 3 copy number in ocular melanoma using fluorescence in situ hybridization

Recent reports have indicated that monosomy 3 is a marker of poor prognosis in uveal melanoma. Fluorescence in situ hybridization (FISH) was performed on fresh touch preparations from 17 uveal, and 5 conjunctival melanomas, using the chromosome 3 centromeric probe, D3Z1. Of the 17 uveal melanomas, all of which originated in the choroid, two cases revealed a monosomy of chromosome 3. One of the conjunctival melanomas contained a major clone that was trisomic for chromosome 3, and another conjunctival melanoma contained a tetrasomic population. FISH, using the alpha-satellite probe for chromosome 3 on uveal melanoma imprints, allows one to predict which patients are potentially at a higher risk of relapse. Multiplication, rather than deletion, of copies of chromosome 3 in conjunctival melanomas may be a nonspecific aberration, perhaps indicative of polyploidy, a characteristic of tumor progression.

Abnormalities of chromosomes 3 and 8 in posterior uveal melanoma correlate with prognosis

Posterior uveal melanomas have nonrandom alterations affecting chromosomes 3, 6, and 8. Loss of chromosome 3 in uveal melanoma has been shown to act as a predictor of disease-free and overall survival. To confirm the significance of chromosome 3 loss and to extend the observations to include those of the associated alterations of chromosome 8, we have conducted a cytogenetic analysis on a series of 42 tumours from patients with primary uveal melanoma who were followed up for a median of 31 months (range = 8-96 months). Abnormalities of chromosomes 3 and 8 were the commonest changes and were confirmed in 10 tumours using fluorescence in situ hybridization. Monosomy of chromosome 3 was found in 21 (50%) of the tumours, and 23 (54%) tumours had additional copies of 8q. Alterations of chromosomes 3 and 8 were found occurring together in 19 (45%) of the tumours and were significantly associated with a ciliary body component (P < 0.0001). Prognostic indicators and changes of chromosomes 3 and 8 were analysed for correlation with patient survival. Of the chosen parameters, only ciliary body involvement (P = 0.003), monosomy of chromosome 3 (P = 0.0007), and additional copies of 8q (P = 0.003) correlated with reduced survival. Evaluation of the dosage effect of additional copies of chromosome arm 8q showed a significant association with reduced survival (P = 0.0001), which was also predictive of a decreased disease-free interval (P = 0.01). Thus, the cytogenetic analysis of uveal melanoma may provide a valuable predictor of prognosis.

Use of fluorescence in situ hybridization and comparative genomic hybridization in the cytogenetic analysis of testicular germ cell tumors and uveal melanomas

Fluorescence in situ hybridization (FISH) with specific DNA probes and comparative genomic hybridization (CGH) are molecular cytogenetic methods that provide powerful supplementations of classical cancer cytogenetics. We present two examples of successful application of these new techniques in solid tumors in which basic information about specific cytogenetic aberrations had been gained previously by conventional karyotyping. In the first, testicular germ cell tumors (TGCT), FISH analysis allowed further characterization of the i(12p) marker chromosome. By CGH, chromosomal subregions that may harbor genes important for tumorigenesis or progression could be identified. In the second, uveal melanoma, CGH enabled a retrospective study in which monosomy 3 was statistically proved to be a relevant marker for poor prognosis.

Acquired homozygosity (isodisomy) of chromosome 3 during clonal evolution of a uveal melanoma: association with morphologic heterogeneity

Cytogenetic investigation of untreated uveal melanoma has shown that the most frequent abnormality is monosomy 3, which occurs in approximately 60% of cases. One of our cases showed distinct pigmented and nonpigmented areas at gross dissection; representative tissue was collected separately from each area, cultured, and harvested using standard cytogenetic techniques. On histologic examination, the pigmented area was found to be composed of small epithelioid cells, whereas the nonpigmented area contained large, pleomorphic epithelioid cells. The karyotype of the pigmented tumor revealed monosomy 3, whereas the nonpigmented tumor showed two apparently normal chromosomes 3. Our purpose in the present study was to investigate the two tumor areas by molecular techniques to determine whether the karyotype of the nonpigmented tumor evolved directly from the pigmented tumor with duplication of the remaining chromosome 3 or whether the two sublines evolved in a divergent fashion from a common precursor stemline. DNA was extracted from normal lymphocytes and separately from both areas of the tumor. The DNA was analyzed using the polymerase chain reaction for polymorphic dinucleotide and tetranucleotide repeat sequences on chromosome 3. Both pigmented and nonpigmented areas of the tumor showed loss of heterozygosity at all informative loci on chromosome 3 that were tested. These results support our hypothesis that an abnormality on chromosome 3 plays a central role in the molecular pathogenesis of uveal melanoma and that some melanomas develop acquired homozygosity (isodisomy) by loss and duplication of the remaining, presumably abnormal, chromosome 3.

Cytogenetics of twelve cases of uveal melanoma and patterns of nonrandom anomalies and isochromosome formation

We present cytogenetic data of 12 new cases of uveal melanoma. One case showed a hypotetraploid chromosome number; the others were near-diploid. Underrepresentation or monosomy of chromosome 3 as well as multiplication of chromosomes 8, 8q, or regions of 8q was found in five cases. Both anomalies were observed in three cases. In two of these, multiplication of 8q resulted from isochromosome formation. The smallest multiplicated region seemed to be 8q23-24-->qter. Chromosome 6 anomalies were found in five cases without monosomy 3. Aberrations of chromosome 21 were seen in five cases and found to be the only cytogenetic change in two of them. These anomalies may define a subgroup of uveal melanoma. An anomaly of chromosome 1 was found in three cases. Anomalies of other chromosomes were detected in at most two cases each. Nonclonal centromeric or telomeric associations were seen in one case and different nonclonal ring chromosomes in another. Underrepresentation of chromosome 3 was seen exclusively in tumors with ciliary body involvement, while anomalies of chromosome 6 were detected only in pure choroideal melanomas. A review of the published cytogenetic data of untreated uveal melanoma supports our finding that monosomy 3 is frequently associated with multiplication of 8q but rarely with anomalies of chromosome 6, whereas the opposite is true for tumors with disomy 3, and that isochromosomes are closely associated with monosomy 3. Thus, cells with monosomy 3 seem to predispose to isochromosome formation.