Phosphorylation of the androgen receptor by PIM1 in hormone refractory prostate cancer.

Integration of cellular signaling pathways with androgen receptor (AR) signaling can be achieved through phosphorylation of AR by cellular kinases. However, the kinases responsible for phosphorylating the AR at numerous sites and the functional consequences of AR phosphorylation are only partially understood. Bioinformatic analysis revealed AR serine 213 (S213) as a putative substrate for PIM1, a kinase overexpressed in prostate cancer. Therefore, phosphorylation of AR serine 213 by PIM1 was examined using a phosphorylation site-specific antibody. Wild-type PIM1, but not catalytically inactive PIM1, specifically phosphorylated AR but not an AR serine-to-alanine mutant (S213A). In vitro kinase assays confirmed that PIM1 can phosphorylate AR S213 in a ligand-independent manner and cell type-specific phosphorylation was observed in prostate cancer cell lines. Upon PIM1 overexpression, AR phosphorylation was observed in the absence of hormone and was further increased in the presence of hormone in LNCaP, LNCaP-abl and VCaP cells. Moreover, phosphorylation of AR was reduced in the presence of PIM kinase inhibitors. An examination of AR-mediated transcription showed that reporter gene activity was reduced in the presence of PIM1 and wild-type AR, but not S213A mutant AR. Androgen-mediated transcription of endogenous PSA, Nkx3.1 and IGFBP5 was also decreased in the presence of PIM1, whereas IL6, cyclin A1 and caveolin 2 were increased. Immunohistochemical analysis of prostate cancer tissue microarrays showed significant P-AR S213 expression that was associated with hormone refractory prostate cancers, likely identifying cells with catalytically active PIM1. In addition, prostate cancers expressing a high level of P-AR S213 were twice as likely to be from biochemically recurrent cancers. Thus, AR phosphorylation by PIM1 at S213 impacts gene transcription and is highly prevalent in aggressive prostate cancer.

Molecular characterisation of ERG, ETV1 and PTEN gene loci identifies patients at low and high risk of death from prostate cancer.

BACKGROUND: The discovery of ERG/ETV1 gene rearrangements and PTEN gene loss warrants investigation in a mechanism-based prognostic classification of prostate cancer (PCa). The study objective was to evaluate the potential clinical significance and natural history of different disease categories by combining ERG/ETV1 gene rearrangements and PTEN gene loss status. METHODS: We utilised fluorescence in situ hybridisation (FISH) assays to detect PTEN gene loss and ERG/ETV1 gene rearrangements in 308 conservatively managed PCa patients with survival outcome data. RESULTS: ERG/ETV1 gene rearrangements alone and PTEN gene loss alone both failed to show a link to survival in multivariate analyses. However, there was a strong interaction between ERG/ETV1 gene rearrangements and PTEN gene loss (P<0.001). The largest subgroup of patients (54%), lacking both PTEN gene loss and ERG/ETV1 gene rearrangements comprised a 'good prognosis' population exhibiting favourable cancer-specific survival (85.5% alive at 11 years). The presence of PTEN gene loss in the absence of ERG/ETV1 gene rearrangements identified a patient population (6%) with poorer cancer-specific survival that was highly significant (HR=4.87, P<0.001 in multivariate analysis, 13.7% survival at 11 years) when compared with the 'good prognosis' group. ERG/ETV1 gene rearrangements and PTEN gene loss status should now prospectively be incorporated into a predictive model to establish whether predictive performance is improved. CONCLUSIONS: Our data suggest that FISH studies of PTEN gene loss and ERG/ETV1 gene rearrangements could be pursued for patient stratification, selection and hypothesis-generating subgroup analyses in future PCa clinical trials and potentially in patient management.

Epidermal growth factor receptor activation in prostate cancer by three novel missense mutations.

While epidermal growth factor receptor (EGFR) dysregulation is known to play a critical role in prostate carcinogenesis, there has been no direct evidence indicating EGFR mutations induce tumorigenesis in prostate cancer. We previously identified four novel EGFR somatic mutations in the EGFR tyrosine kinase domain of prostate cancer patients: G735S, G796S, E804G and R841K. In this study, we investigated the oncogenic potential of these somatic mutations by establishing stable clonal NIH3T3 cells expressing these four mutations and WT EGFR to determine their ability to increase cell proliferation and invasion. In the absence of the EGF ligand, cell proliferation was readily increased in G735S, G796S and E804G mutants compared to WT EGFR. The addition of EGF ligand greatly increased cell growth and transforming ability of these same EGFR mutants. Matrigel invasion assays showed enhanced invasion with G735S, G796S and E804G mutants. Western blot analysis showed that these EGFR mutations enhanced cell growth and invasion via constitutive and hyperactive tyrosine phosphorylation and led to the activation of mitogen-activated protein kinase (MAPK), signal transducer and activator of transcription 3 (STAT3) and Akt pathways. Our findings demonstrate the oncogenic activation of three novel EGFR somatic missense mutations in prostate cancer. Molecules that regulate the mechanisms of their oncogenic activation represent novel targets for limiting tumor cell progression, and further elucidation of these mutations will have utility in prostate cancer treatment.

Duplication of the fusion of TMPRSS2 to ERG sequences identifies fatal human prostate cancer.

New predictive markers for managing prostate cancer are urgently required because of the highly variable natural history of this disease. At the time of diagnosis, Gleason score provides the gold standard for assessing the aggressiveness of prostate cancer. However, the recent discovery of TMPRSS2 fusions to the ERG gene in prostate cancer raises the possibility of using alterations at the ERG locus as additional mechanism-based prognostic indicators. Fluorescence in situ hybridization (FISH) assays were used to assess ERG gene status in a cohort of 445 prostate cancers from patients who had been conservatively managed. The FISH assays detected separation of 5' (labelled green) and 3' (labelled red) ERG sequences, which is a consequence of the TMPRSS2-ERG fusion, and additionally identify interstitial deletion of genomic sequences between the tandemly located TMPRSS2 and ERG gene sequences on chromosome 21. Cancers lacking ERG alterations exhibited favourable cause-specific survival (90% survival at 8 years). We identify a novel category of prostate cancers, characterized by duplication of the fusion of TMPRSS2 to ERG sequences together with interstitial deletion of sequences 5' to ERG (called '2+Edel'), which by comparison exhibited extremely poor cause-specific survival (hazard ratio=6.10, 95% confidence ratio=3.33-11.15, P<0.001, 25% survival at 8 years). In multivariate analysis, '2+Edel' provided significant prognostic information (P=0.003) in addition to that provided by Gleason score and prostate-specific antigen level at diagnosis. Other individual categories of ERG alteration were associated with intermediate or good prognosis. We conclude that determination of ERG gene status, including duplication of the fusion of TMPRSS2 to ERG sequences in 2+Edel, allows stratification of prostate cancer into distinct survival categories.

An estrogen receptor-negative breast cancer subset characterized by a hormonally regulated transcriptional program and response to androgen.

Little is known of the underlying biology of estrogen receptor-negative, progesterone receptor-negative (ER(-)/PR(-)) breast cancer (BC), and few targeted therapies are available. Clinical heterogeneity of ER(-)/PR(-) tumors suggests that molecular subsets exist. We performed genome-wide expression analysis of 99 primary BC samples and eight BC cell lines in an effort to reveal distinct subsets, provide insight into their biology and potentially identify new therapeutic targets. We identified a subset of ER(-)/PR(-) tumors with paradoxical expression of genes known to be either direct targets of ER, responsive to estrogen, or typically expressed in ER(+) BC. Differentially expressed genes included SPDEF, FOXA1, XBP1, CYB5, TFF3, NAT1, APOD, ALCAM and AR (P<0.001). A classification model based on the expression signature of this tumor class identified molecularly similar BCs in an independent human BC data set and among BC cell lines (MDA-MB-453). This cell line demonstrated a proliferative response to androgen in an androgen receptor-dependent and ER-independent manner. In addition, the androgen-induced transcriptional program of MDA-MB-453 significantly overlapped the molecular signature of the unique ER(-)/PR(-) subclass of human tumors. This subset of BCs, characterized by a hormonally regulated transcriptional program and response to androgen, suggests the potential for therapeutic strategies targeting the androgen signaling pathway.

Identifying site-specific metastasis genes and functions.

Metastasis is a multistep and multifunctional biological cascade that is the final and most life-threatening stage of cancer progression. Understanding the biological underpinnings of this complex process is of extreme clinical relevance and requires unbiased and comprehensive biological scrutiny. In recent years, we have utilized a xenograft model of breast cancer metastasis to discover genes that mediate organ-specific patterns of metastatic colonization. Examination of transcriptomic data from cohorts of primary breast cancers revealed a subset of site-specific metastasis genes that are selected for early in tumor progression. High expression of these genes predicts the propensity for lung metastasis independently of several classic markers of poor prognosis. These genes fulfill dual functions-enhanced primary tumorigenicity and augmented organ-specific metastatic activity. Other metastasis genes fulfill functions specialized for the microenvironment of the metastatic site and are consequently not selected for in primary tumors. These findings improve our understanding of metastatic progression, facilitate the interpretation of primary tumor gene expression data, and open several important possibilities for future clinical application.

Comprehensive analysis of the 9p21 region in neuroblastoma suggests a role for genes mapping to 9p21-23 in the biology of favourable stage 4 tumours.

Chromosome 9p21 is frequently deleted in many cancers. Previous reports have indicated that 9p21 LOH is an uncommon finding in neuroblastoma (NB), a tumour of childhood. We have performed an extensive analysis of 9p21 and genes located in this region (cyclin-dependent kinase inhibitor 2A - CDKN2A/p16(INK4a), CDKN2A/p14(ARF), CDKN2B/p15(INK4b), MTAP, interferon alpha and beta cluster). LOH was detected in 16.4% of 177 NB. The SRO was identified between markers D9S1751 and D9S254, at 9p21-23, a region telomeric to the CDKN2A and MTAP genes. A significantly better overall and progression-free survival was detected in stage 4 patients displaying 9p21-23 LOH. Hemizygous deletion of the region harbouring the CDKN2A and CDKN2B loci was identified in two tumours by means of fluorescent in situ hybridisation and MTAP was present by immunostaining in all but one tumour analysed. The transcriptional profile of tumours with 9p21-23 LOH was compared to that of NB displaying normal 9p21-23 status by means of oligonucleotide microarrays. Four of the 363 probe sets downregulated in tumours with 9p21-23 LOH were encoded by genes mapping to 9p22-24. The only well-characterised transcript among them was nuclear factor I-B3. Our results suggest a role for genes located telomeric of 9p21 in good risk NB.

Neuroblastic and Schwannian stromal cells of neuroblastoma are derived from a tumoral progenitor cell.

The coexistence of neuroblastic and Schwannian stromal (SS) cells in differentiating neuroblastoma (NB), and derivation of Schwannian-like cells from neuroblastic clones in vitro, were accepted previously as evidence of a common pluripotent tumor stem line. This paradigm was challenged when SS cells were suggested to be reactive in nature. The advent of microdissection techniques, PCR-based allelic analysis, and in situ fluorescent cytometry made possible the analysis of pure cell populations in fresh surgical specimens, allowing unequivocal determination of clonal origins of various cell subtypes. To overcome the complexity and heterogeneity of three-dimensional tissue structure, we used: (a) Laser-Capture Microdissection to obtain histologically homogeneous cell subtype populations for allelotype analysis at chromosomes 1p36, 11q23, 14q32, and 17q and study of MYCN copy number; (b) multiparametric analysis by Laser-Scanning Cytometry of morphology, DNA content, and immunophenotype of intact cells from touch imprints; and (c) bicolor fluorescence in situ hybridization on touch imprints from manually microdissected neuroblast and stroma-rich areas. Histologically distinct SS and neuroblastic cells isolated by Laser-Capture Microdissection had the same genetic composition in 27 of 28 NB analyzed by allelic imbalance and gene copy number. In all 20 cases studied by Laser-Scanning Cytometry, SS cells identified by morphology and S-100 immunostaining had identical DNA content and GD2-staining pattern as their neuroblastic counterparts. In 7 cases, fluorescence in situ hybridization demonstrated the same chromosomal makeup for SS and neuroblastic cells. These results provide unequivocal evidence that neuroblastic and SS cells in NB are derived from genetically identical neoplastic cells and support the classical paradigm that NB arises from tumoral cells capable of development along multiple lineages.

Biological behavior of human breast cancer micrometastases.

PURPOSE: Clinically undetectable micrometastases may account for disease recurrence in breast cancer patients after variable disease-free intervals. However, little is known about the cellular mechanisms controlling human breast cancer micrometastases. We compared tumor proliferation rate, apoptotic index, and angiogenesis in human breast cancer micrometastases with those of macroscopic axillary lymph node metastases. EXPERIMENTAL DESIGN: Seven breast cancer micrometastases (<2 mm) obtained from the sentinel nodes of seven patients were compared with 13 macrometastases (lymph node replaced with tumor) obtained from 13 patients. The tissue was fixed in formalin, embedded in paraffin, serially sectioned, and evaluated by H&E and immunohistochemistry for cytokeratin. Tumor proliferation rate was assessed as the number of Ki-67-positive nuclei/total number of tumor nuclei. Tumor vascularity was quantified using antibody to factor VIII to identify microvessels per high-power field (at x400). Apoptosis was quantified using the terminal deoxynucleotidyl transferase (Tdt)-mediated nick end labeling method. Results were analyzed with the Wilcoxon rank-sum test. RESULTS: Median size of micrometastases was 0.5 mm (range, 0.4-1.0), and the median number of tumor nuclei/section was 143 (range, 90-312). Median proliferation rate for macrometastases was greater than for micrometastases (35% versus 12%; P = 0.003). Median microvessel density/high-power field for macrometastases was greater than for micrometastases (17 versus 1; P < 0.001). There was no difference in apoptotic index between macrometastases and micrometastases (1.1% versus 0.7%; P = not significant). CONCLUSIONS: Human breast cancer micrometastases have lower tumor proliferation rates and angiogenesis than breast cancer macrometastases. These characteristics may explain their differential growth patterns.

Genetic heterogeneity and clonal evolution in neuroblastoma.

Tumour heterogeneity and clonal evolution at the genetic level may explain the development of malignant or resistant disease during clinical progression of neuroblastoma (NB). In this report we use 1p allelic analysis and DNA ploidy to evaluate clonal heterogeneity and clonal selection in vivo. We studied a total of 69 tumours from 29 patients with NB. To evaluate tumour heterogeneity and clonal evolution in vivo we used a panel of polymorphic allelic markers mapping to chromosome 1. 33 tumours from 12 patients (group 1) were obtained from different sites during the same surgery or at sequential surgeries without intervening chemotherapy to evaluate genetic heterogeneity. Paired samples from 10 patients (group 2) were used to evaluate clonal selection before and after chemotherapy. In 6 cases paired tumours and derived cell lines were studied. Analysis of DNA ploidy changes by karyotype, FISH and flow cytometry was performed in 15 tumours from 6 multiply recurred local-regional (LR) NB patients. Allelotype study revealed that 66% (8/12) of group 1 samples were heterogeneous, with distinct allelic patterns in tumour samples separated by time or location. In group 2 allelic patterns were different in post-chemotherapy specimens in 60% (6/10). DNA ploidy analysis showed that pre-chemotherapy samples contained 2 distinct ploidy clones, one diploid and one triploid, whereas all post-chemotherapy tumor samples were 100% diploid. These findings suggest that NB exhibits a high degree of clonal heterogeneity and clonal evolution occurs during the course of therapy and clinical progression.

Disaloganglioside GD2 loss following monoclonal antibody therapy is rare in neuroblastoma.

BACKGROUND: Gangliosicle GD2 is abundant on human neuroblastoma (NB). Monoclonal antibody 3F8 targeted to GD2 may have imaging and therapeutic potential. Antigen-negative clones can escape immune-mediated attack leading to clinical resistance or recurrence. PROCEDURE: Among 95 evaluable patients treated intravenously with 3F8 (94 Stage 4, 1 Stage 3), 66 received nonradiolabeled 3F8, 11 received 131-iodine-labeled-3F8 (8-28 mCi/kg) with autologous bone marrow rescue, and 18 received both forms of treatment. Prior to treatment, 90 patients tested positive for GD2 reactivity by bone marrow immunofluorescence (n = 68), tumor immunohistochemistry (n = 20), or diagnostic radioimmunoscintigraphy (n = 2). RESULTS: Of 62 patients who had refractory or recurrent neuroblastoma following 3F8 treatment, 61 (98%) tested positive for GD2 reactivity by bone marrow immunofluorescence (n = 51) or tumor immunohistochemistry (n = 10). The sole tumor that lost GD2 expression underwent phenotypic transformation into a pheochromocytoma-like tumor. CONCLUSIONS: The persistence of GD2 expression in refractory or recurrent NB suggests that complete antigen loss is an uncommon event and cannot account for treatment failure.

Molecular genetics of neuroblastoma and the implications for clinical management: a review of the MSKCC experience.

Neuroblastoma (NB) is a biological, genetic, and morphological heterogeneous neoplasm and demonstrates diverse clinical behavior. There exist at least three clinical patterns of NB: A) spontaneously regressing widespread disease; B) not metastatic local-regional disease, and C) metastatic disease (stage 4), frequently with lethal consequences. Patients with non-stage 4 NB are expected to survive even without medical treatment whereas stage 4 patients have an overall survival rate of 20% despite multimodality therapy protocols. The clinical management of patients with NB is therefore challenged by the objective identification of cases in which noncytotoxic approaches can be safely taken. Experience in the last decade at Memorial Sloan-Kettering Cancer Center supports the hypothesis that the natural history of disease defines relevant clinical groups of NB and has distinct molecular genetic profiles allowing therapeutic approaches tailored for each group. Here we review the natural history and clinicobiological features of 113 NB cases managed uniformly in our institution in an attempt to characterize useful genetic markers to support the decision making of noncytotoxic versus cytotoxic approaches for each category of NB.

Inactivation of the apoptosis effector Apaf-1 in malignant melanoma.

Metastatic melanoma is a deadly cancer that fails to respond to conventional chemotherapy and is poorly understood at the molecular level. p53 mutations often occur in aggressive and chemoresistant cancers but are rarely observed in melanoma. Here we show that metastatic melanomas often lose Apaf-1, a cell-death effector that acts with cytochrome c and caspase-9 to mediate p53-dependent apoptosis. Loss of Apaf-1 expression is accompanied by allelic loss in metastatic melanomas, but can be recovered in melanoma cell lines by treatment with the methylation inhibitor 5-aza-2'-deoxycytidine (5aza2dC). Apaf-1-negative melanomas are invariably chemoresistant and are unable to execute a typical apoptotic programme in response to p53 activation. Restoring physiological levels of Apaf-1 through gene transfer or 5aza2dC treatment markedly enhances chemosensitivity and rescues the apoptotic defects associated with Apaf-1 loss. We conclude that Apaf-1 is inactivated in metastatic melanomas, which leads to defects in the execution of apoptotic cell death. Apaf-1 loss may contribute to the low frequency of p53 mutations observed in this highly chemoresistant tumour type.

Laser-capture microdissected schwannian and neuroblastic cells in stage 4 neuroblastomas have the same genetic alterations.

BACKGROUND: Neuroblastoma (NB) is a heterogeneous tumor composed of mixed populations of neuroblastic, Schwannian, and gangliocytic cells. PROCEDURE: We examined the genetic lineage of Schwannian and neuroblastic cells in stage 4 NB using laser-capture microdissection (LCM) and allelic analysis of microsatellite markers of chromosomes 1p, 11q, and 14q. RESULTS: In 18 out of 19 cases, individual cell types exhibited the same allelotype. CONCLUSION: Our results provide evidence that the majority of Schwannian and neuroblastic cells in stage 4 NB are of neoplastic origin, and support the hypothesis of a tumor stem cell capable of development along multiple lineages.

Molecular biology of the Ewing's sarcoma/primitive neuroectodermal tumor family.

Ewing's sarcoma (ES) and primitive neuroectodermal tumor (PNET) are members of a tumor family consistently associated with chromosomal translocation and functional fusion of the EWS gene to any of several structurally related transcription factor genes. Similar gene fusion events occur in other mesenchymal and hematopoietic tumors and are tumor-specific. The resulting novel transcription factor-like chimeric proteins are believed to contribute to tumor biology by aberrant regulation of gene expression altering critical controls of cell proliferation and differentiation. These tumor-specific molecular rearrangements are useful for primary diagnosis, may provide prognostic information, and present potential therapeutic targets. The recent advances in our understanding of the molecular biology of ES and PNET represent a paradigm for the application of the basic biology of neoplasia to clinical management of patients.

Clinical categories of neuroblastoma are associated with different patterns of loss of heterozygosity on chromosome arm 1p.

Deletion of the short arm of chromosome 1 is frequently observed in neuroblastoma (NB). We performed loss of heterozygosity (LOH) analysis of 120 well characterized NB to better define specific regions of 1p loss and any association with clinical and biological prognostic features (DNA index, MYCN, age, and stage). All categories of disease were represented including 7 ganglioneuromas, 8 stage 4S, 33 local-regional (stages 1, 2, and 3), and 72 stage 4 NB according to the International Neuroblastoma Staging System. Patients were consistently treated with stage-appropriate protocols at a single institution. Sixteen highly informative, polymorphic loci mapping to chromosome 1 were evaluated using a sensitive, semi-automated, fluorescent detection system. Chromosome arm 1p deletions were detected in all categories of tumor except ganglioneuroma. Frequent LOH was detected at two separate regions of 1p and distinct patterns of losses were associated with individual clinical/biological categories. Clinically aggressive stage 4 tumors were predominantly diploid with extensive LOH frequently detected in the region of 1ptel to 1p35 (55%) and at 1p22 (56%). The shortest region of overlap for LOH at 1p36 was between D1S548 and D1S1592 and for 1p22 was between D1S1618 and D1S2766. Local-regional tumors were mostly hyperdiploid with short regions of loss primarily involving terminal regions of 1p36 (42%). Most spontaneously regressing stage 4S tumors (7/8) were hyperdiploid without loss of 1p36 or 1p22. These findings suggest that genes located on at least two separate regions of chromosome arm 1p play a significant role in the biology of NB and that distinct patterns of 1p LOH occur in individual clinical/biological categories.

Clinically critical impact of molecular genetic studies in pediatric solid tumors.

BACKGROUND: Standard cytogenetic techniques are time-consuming and often not informative with solid tumors. In contrast, the reverse transcriptase-polymerase chain reaction (RT-PCR) is a readily available technique that can rapidly detect tumor-specific chromosomal rearrangements, even in small biopsy specimens. We present cases depicting the importance of including molecular diagnostic studies in the routine evaluation of pediatric solid tumors. PROCEDURE: We used RT-PCR to detect chimeric transcripts specific for major pediatric solid tumors, including peripheral primitive neuroectodermal tumor (pPNET), alveolar rhabdomyosarcoma (ARMS), and desmoplastic small round-cell tumor (DSRCT). We reviewed six recent cases in which the initial diagnosis was changed by the results of RT-PCR. RESULTS: Highly unusual or nonspecific clinical and/or histopathologic findings led to the initial diagnoses of neuroblastoma in three patients and DSRCT, leukemia, and carcinoma in one patient each. The final diagnoses after RT-PCR studies were pPNET in three patients, ARMS in two patients, and DSRCT in one patient. RT-PCR results led to early corrections in the diagnosis in two patients, but four patients received treatment not considered optimal for the neoplasms ultimately diagnosed, including three who, despite presenting with localized tumors that have a >70% cure rate with standard therapy, have died or are dying of disease. CONCLUSIONS: Molecular genetic studies on solid tumors can clarify the diagnosis in seemingly straightforward as well as in overtly problematic cases. These diagnostic distinctions are now critical as disease-specific and risk-directed therapies have emerged.

Synovial sarcoma mimicking desmoplastic small round-cell tumor: critical role for molecular diagnosis.

BACKGROUND: The identification of recently described nonrandom chromosomal defects specific for various small round-cell and spindle-cell sarcomas can eliminate diagnostic uncertainty arising from the clinical and histopathologic overlap of soft tissue neoplasms. METHODS: A 26-year-old man presented with bulky abdominal-pelvic disease. Immunohistochemical and molecular studies on tumor were performed. Treatment was instituted using cycles of high-dose cyclophosphamide (4,200 mg/m2) with doxorubicin (75 mg/m2). RESULTS: Clinical findings pointed to desmoplastic small round-cell tumor. The tumor was histologically undifferentiated and immunoreactive for vimentin but negative for other markers. Reverse transcriptase-polymerase chain reaction revealed the SYT/SSX2 fusion transcript of the synovial sarcoma t(X;18) chromosomal rearrangement. The high-dose chemotherapy, plus surgery, achieved a complete remission, but recurrent disease emerged 13 months from diagnosis. CONCLUSIONS: This clinically unique case of synovial sarcoma highlights how the use of now readily available molecular techniques will allow more accurate appraisals of the incidence and anatomic distribution of soft tissue neoplasms-information that bears upon pathogenesis and treatment. This case confirms the utility of high-dose alkylator-based therapy for synovial sarcoma. It also demonstrates that with nonlocalized solid tumors, the eradication of minimal residual disease remains an elusive goal. One alternative involves immunologic attack against markers derived from tumor-specific chromosomal defects such as those found in our patient.