A CASE OF ADVANCED NON-SEMINOMATOUS TESTICULAR GERM CELL TUMOR ACCOMPANIED PANIC DISORDER.

We report a 33-year-old male with a left advanced non-seminomatous testicular germ cell tumor (NSGCT) accompanied panic disorder. He had experienced palpitation and hyperpnea in crowds in his twenties. He was admitted to the Department of Otorhinolaryngology with the chief complaint of left neck swelling. 18F-fluorodeoxy glucose positron emission tomography/computed tomography (FDG-PET/CT) demonstrated left neck, left supraclavicular, left axillary, and paraaortic lymph node (LN) swelling and left testicular swelling. He was referred to our department. The left testis had enlarged to the size of a fist. He rejected admission at that time, but next day, he was taken to our hospital by an ambulance because he lost consciousness at home. No abnormalities were found in the brain CT and electrocardiogram. He was admitted and left high orchiectomy was performed. The human chorionic gonadotropin (HCG) level had elevated to 9,717 IU/L and alpha fetoprotein level (AFP) had elevated to 427 ng/ml. The histopathological diagnosis was tumors of more than one histological type, mixed forms: seminoma and embryonal carcinoma.He had palpitation and hyperpnea after admission and was diagnosed with panic disorder by a psychiatrist. Psychotropic drugs (fluvoxamine maleate 50 mg/day, alprazolam 0.8 mg/day) were prescribed and the panic attacks disappeared afterwards. The psychiatric social worker supported his mind side. Bleomycin, etoposide, and cisplatin (BEP) therapy was performed for 4 courses. He put on a blanket to his face and came to avoid a conversation with other people during the chemotherapy. He was diagnosed with depression and psychotropic drugs were increased (fluvoxamine maleate 50→75 mg/day, alprazolam 0.8→1.2 mg/day) in quantity.Lymphadenectomies for LN metastases were performed and their histopathological examination revealed the existence of viable embryonal carcinoma in the supraclavicular LN. Etoposide, ifosfamide, and cisplatin (VIP) therapy was performed for 2 courses.The pateint has remained alive without tumor recurrence. Psychotropic drugs were reduced and the recent drug is fluvoxamine maleate 25 mg/day.

A case of mediastinal embryonal carcinoma successfully treated by integrative therapy.

Mediastinal embryonal carcinoma is rare, and the life prognosis of this disease is assumed to be relatively short. We encountered a case of mediastinal embryonal carcinoma for which we could perform radical surgical resection. The patient was male, aged 16 years, and acutely aware of back pain. Because the pain increased during the same year, he visited a local doctor, and an expanding neoplastic lesion was detected in the right thoracic wall by computed tomography (CT). Then he was referred to our institution. Magnetic resonance imaging (MRI) showed a dumbbell type tumor (Eden type 3) at the Th7/8 level. Malignant disease was suspected, so the authors planned and performed CT-guided biopsy. The result showed that this tumor pathologically corresponded to malignant peripheral nerve sheath tumor (MPNST). Therefore, chemotherapy was considered the main treatment. After 2 courses of chemotherapy, the tumor size decreased dramatically. The authors thought that radical resection is possible if there is no intrathoracic tumor dissemination as a result of a favorable response to chemotherapy. We thus perfomed surgical resection after we confirmed by a thoracoscopic exploratory thoracotomy that there was no intrathoracic tumor dissemination. Pathological findings were consistent with an embryonal carcinoma. Both the cutting ends of the thoracic wall and the epidural lateral sides of the excised lesion were negative for tumor cells. There is no image finding from the MRI and PET-CT suggesting metastasis or recurrence in the MRI and PET-CT 18 months after surgical resection. Therefore, the long-term vital prognosis can be expected in this patient.

Therapeutic potential of SOX2 inhibition for embryonal carcinoma.

PURPOSE: Some nonseminomatous germ cell tumors are resistant to any type of chemotherapy. Control of embryonal carcinoma cells is crucial to manage nonseminomatous germ cell tumors. We established SOX2 targeting therapy in an embryonal carcinoma model. MATERIALS AND METHODS: SOX2 expression was evaluated in a series of testicular germ cell tumor tissue samples. The antitumor effect of SOX2 knockdown was analyzed in vitro and in vivo using an embryonal carcinoma model. RESULTS: In testicular germ cell tumor tissue SOX2 was expressed in the foci of embryonal carcinoma but negative in seminoma and yolk sac tumors. In an embryonal carcinoma model SOX2-siRNA induced apoptotic cell death in vitro and significant growth suppression in vivo. CONCLUSIONS: This study shows the therapeutic potential of SOX2 silencing for embryonal carcinoma. However, further improvements are needed in SOX2-siRNA delivery to the tumor.

Management of primary intracranial germ cell tumors.

Primary intracranial germ cell tumors are rare and usually localized in the pineal and the suprasellar regions. They are divided into the following histologic types: germinoma, teratoma (mature, immature, malignant), choriocarcinoma, embryonal carcinoma, endodermal sinus tumor (yolk sac tumor), and mixed tumors. Clinically, they are manifested with ocular signs or signs of obstructive hydrocephalus. Localized germinomas are treated with radiation therapy and exhibit a relatively good prognosis. Chemotherapy is reserved for disseminated germinomas. Mature teratomas are treated with surgery. The rest of germ cell tumors are managed with various combinations of surgery, chemotherapy, and radiotherapy depending on the tumor type. If the tumors secrete beta-human chorionic gonadotrophin (hCG) or alpha-fetoprotein (FP), these tumor markers can be used to accurately monitor response to treatment. Prognosis is best for germinomas and mature teratomas and worst for choriocarcinomas and embryonal carcinomas.

Retroperitoneal lymph node dissection in patients with high risk testicular cancer.

PURPOSE: In patients with testicular cancer the percent of embryonal carcinoma and lymphovascular invasion in the primary tumor have been identified as risk factors for occult metastatic disease. We reviewed differences between primary and post-chemotherapy retroperitoneal lymph node dissection in patients at high risk. MATERIALS AND METHODS: Patients who underwent retroperitoneal lymph node dissection at our institution from 1993 to 2006 were identified and the clinical charts were reviewed. A total of 247 patients with orchiectomy specimens containing greater than 30% embryonal carcinoma were identified and perioperative data were obtained. RESULTS: Of 247 patients 133 (53%) had greater than 30% embryonal carcinoma, including 76 (57%) with combined lymphovascular invasion. Median followup was 3.49 years. Of the patients 76 (57%) and 57 (43%) underwent primary and post-chemotherapy retroperitoneal lymph node dissection, respectively, of whom most received bleomycin, etoposide and cisplatin. Positive lymph nodes were identified at surgery in 37 (49%) and 35 patients (61%) with primary and post-chemotherapy retroperitoneal lymph node dissection, respectively. Of patients with negative pathological findings at surgery surveillance computerized tomography postoperatively identified retroperitoneal masses in 2 (5%) and 3 (14%) of those who underwent a primary and a post-chemotherapy procedure, respectively. Operative data on the primary vs post-chemotherapy groups showed an estimated blood loss of 166 vs 371 cc, an operative time of 2.7 vs 3.3 hours and a hospital stay of 4.4 vs 4.7 days. There were no deaths in either group. CONCLUSIONS: Patients with greater than 30% embryonal carcinoma with or without lymphovascular invasion are at significant risk for metastatic disease and they can be successfully treated with primary retroperitoneal lymph node dissection. Recurrence rates based on computerized tomography evaluation were low and similar between the chemotherapy and nonchemotherapy treated groups.

Emergency management of a particular massive pulmonary embolism...

Cardiac intracavitary metastasis is very uncommon. In a 55-year-old man presenting with a massive pulmonary embolism pattern, transthoracic echocardiography (TTE) allowed us to visualize an isolated right ventricular metastasis extended into the pulmonary trunk. It led to the discovery of a primary testis embryonal carcinoma. No intracaval and right atrial localization was observed. Despite an urgent complete cardiac metastasis resection and concomitant orchidectomy, TTE showed on postoperative day 6 an uncommon total intracardiac regrowth spreading again to the pulmonary trunk. Combination chemotherapy (etoposide, cisplatin, and bleomycin) was immediately undertaken. This is the first well-documented case of an isolated right ventricular germ-cell cancer metastasis extended into the pulmonary trunk, without intracaval and right atrial involvement, where the outcome was marked with immediate regrowth despite cardiac surgery and orchidectomy. In conclusion, TTE should be considered alongside germ-cell cancer standard staging procedures.

Treatment of Relapse of Clinical Stage I Nonseminomatous Germ Cell Tumors on Surveillance.

PURPOSE: Active surveillance (AS) for testicular nonseminomatous germ cell tumors (NSGCT) is widely used. Although there is no consensus for optimal treatment at relapse on surveillance, globally patients typically receive chemotherapy. We describe treatment of relapses in our non-risk-adapted NSGCT AS cohort and highlight selective use of primary retroperitoneal lymph node dissection (RPLND). METHODS: From December 1980 to December 2015, 580 patients with clinical stage I NSGCT were treated with AS, and 162 subsequently relapsed. First-line treatment was based on relapse site and extent. Logistic regression was used to explore factors associated with need for multimodal therapy on AS relapse. RESULTS: Median time to relapse was 7.4 months. The majority of relapses were confined to the retroperitoneum (66%). After relapse, first-line treatment was chemotherapy for 95 (58.6%) and RPLND for 62 (38.3%), and five patients (3.1%) underwent other therapy. In 103 (65.6%), only one modality of treatment was required: chemotherapy only in 58 of 95 (61%) and RPLND only in 45 of 62 (73%). Factors associated with multimodal relapse therapy were larger node size (odds ratio, 2.68; P = .045) in patients undergoing chemotherapy and elevated tumor markers (odds ratio, 6.05; P = .008) in patients undergoing RPLND. When RPLND was performed with normal markers, 82% required no further treatment. Second relapse occurred in 30 of 162 patients (18.5%). With median follow-up of 7.6 years, there were five deaths (3.1% of AS relapses, but 0.8% of whole AS cohort) from NSGCT or treatment complications. CONCLUSION: The retroperitoneum is the most common site of relapse in clinical stage I NSGCT on AS. Most are cured by single-modality treatment. RPLND should be considered for relapsed patients, especially those with disease limited to the retroperitoneum and normal markers, as an option to avoid chemotherapy.

Analysis of the Paternally-Imprinted DLK1-MEG3 and IGF2-H19 Tandem Gene Loci in NT2 Embryonal Carcinoma Cells Identifies DLK1 as a Potential Therapeutic Target.

The paternally-imprinted genes insulin-like growth factor 2 (IGF2), H19, delta-like homologue 1 (DLK1), and maternally-expressed gene 3 (MEG3) are expressed from the tandem gene loci IGF2-H19 and DLK1-MEG3, which play crucial roles in initiating embryogenesis and development. The erasure of imprinting (EOI) at differentially methylated regions (DMRs) which regulate the expression of these genes maintains the developmental quiescence of primordial germ cells (PGCs) migrating through the embryo proper during embryogenesis and prevents them from forming teratomas. To address the potential involvement of the IGF2-H19 and DLK1-MEG3 loci in the pathogenesis of embryonal carcinoma (EC), we investigated their genomic imprinting at DMRs in the human PGC-derived EC cell line NTera-2 (NT2). We observed EOI at the IGF2-H19 locus and, somewhat to our surprise, a loss of imprinting (LOI) at the DLK1-MEG3 locus. As a result, NT2 cells express imprinted gene ratios from these loci such that there are i) low levels of the proliferation-promoting IGF2 relative to ii) high levels of the proliferation-inhibiting long noncoding RNA (lncRNA) H19 and iii) high levels of proliferation-promoting DLK1 relative to iv) low levels of the proliferation-inhibiting lncRNA MEG3. Consistent with this pattern of expression, the knockdown of DLK1 mRNA by shRNA resulted in decreased in vitro cell proliferation and in vivo tumor growth as well as decreased in vivo organ seeding by NT2 cells. Furthermore, treatment of NT2 cells with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-azaD) inhibited their proliferation. This inhibition was accompanied by changes in expression of both tandem gene sets: a decrease in the expression of DLK1 and upregulation of the proliferation-inhibiting lncRNA MEG3, and at the same time upregulation of IGF2 and downregulation of the lncRNA H19. These results suggest that the DLK1-MEG3 locus, and not the IGF2-H19 locus, drives the tumorigenicity of NT2 cells. Based on these results, we identified DLK1 as a novel treatment target for EC that could be downregulated by 5-azaD.

Clinical Outcome of Retroperitoneal Lymph Node Dissection after Chemotherapy in Patients with Pure Embryonal Carcinoma in the Orchiectomy Specimen.

OBJECTIVE: To determine the pathologic findings and clinical outcome of patients with pure embryonal carcinoma (EC) of the testis who were diagnosed with testis cancer from January 1989 to January 2013 who underwent an orchiectomy, cisplatin-based chemotherapy and a postchemotherapy retroperitoneal lymph node dissection (PC-RPLND). METHODS: We compared those patients with 100% EC with those with mixed nonseminomatous germ cell tumor pathology who underwent a PC-RPLND. RESULTS: Of 1105 patients who underwent a PC-RPLND, 145 had pure EC. Twenty-six percent of patients presented with metastatic disease outside the retroperitoneum. Patients with mixed histologies tended to have worse International Germ Cell Cancer Collaborative Group risk compared to those with EC at orchiectomy (P = .037). Histology at PC-RPLND revealed fibrosis or necrosis in 76%, mature teratoma in 19% and viable cancer in 4%. Over one-third of the patients had a residual mass of <1 cm prior to RPLND; of whom 15% harbored mature teratoma in PC-RPLND histology. The Kaplan-Meier estimated probability of recurrence at 5 years of follow-up was 3.1% (95% CI 1.2%, 8.0%) for EC histology, 7.3% lower than mixed histology. For cancer-specific mortality, the Kaplan-Meier estimated probability at 5 years was 4.6% (95% CI 3.3%, 6.3%) and 1.7% (95% CI 0.4%, 6.8%) for mixed and pure EC histologies, respectively. CONCLUSION: Approximately 20% of patients with pure EC had teratoma at PC-RPLND. We have shown that those with a maximum node size of <1 cm should not be precluded from RPLND.

Clinical and Radiologic Features of Pediatric Basal Ganglia Germ Cell Tumors.

BACKGROUND AND OBJECTIVE: Pediatric basal ganglia germ cell tumors (GCTs) represent a rare subset of tumors about which little is known. We aimed to summarize the clinical features and radiological findings of this special subgroup of GCTs. METHODS: From January 2010 to January 2015, 12 pediatric patients with basal ganglia GCTs were treated in our hospital. The clinical features, radiologic findings, diagnosis, treatment, and outcome of these patients were analyzed retrospectively. Our institutional diagnostic principle and treatment strategy of this disease were discussed. RESULTS: GCTs accounted for 25.5% of all the pediatric basal ganglia tumors treated in our hospital. There were 9 male and 3 female patients with a mean age of 11.5 ± 2.1 years. The most common symptom was progressive hemiparesis (n = 9, 75%). The radiologic findings showed that the lesions predominately located in caput of caudate nucleus (n = 9, 75.0%), followed by lenticular nucleus (n = 3, 25.0%). Hemiatrophy was commonly observed (n = 8, 66.7%). Eight patients were diagnosed as having germinomas, and 4 patients as having nongerminomatous germ cell tumors. During the follow-up period, preoperative neurologic dysfunctions improved in 7 patients and remained stable in 3. Two patients developed new onset of neurologic dysfunction after the treatment. Two patients suffered from tumor recurrence. CONCLUSIONS: GCTs are not as rare as considered in pediatric basal ganglia tumors. They bear some distinctive clinical and radiologic features, which can help with the accurate diagnosis and successful management of such tumors.

Late relapse of testicular cancer.

PURPOSE: This study analyzed a large group of patients with testicular germ cell cancer in complete remission, who relapsed more than 2 years after completion of treatment. PATIENTS AND METHODS: A review of all patients treated at Indiana University Medical Center from 1979 through 1992 for late relapse was conducted. Eighty-one patients were treated for late relapse of testicular cancer. Forty-seven patients relapsed more than 5 years after successful management of their initial disease. RESULTS: At initial diagnosis, 35 patients had clinical stage I, 18 stage II, and 28 stage III disease. Twenty-three of 35 stage I, all 18 stage II, and all 28 stage III patients were treated by chemotherapy before their late relapse. The median follow-up duration of patients post-management of late relapse was 4.8 years. Twenty-one patients (25.9%) are continuously disease-free. Nineteen of these 21 patients had surgical resection of carcinoma or teratoma as a component of their therapy. Of sixty-five patients treated for late relapse by chemotherapy, 17 (26.2%) had a complete response, but only two have been continuously disease-free with chemotherapy alone. These two never received prior chemotherapy. CONCLUSION: Late relapse of testis cancer is more common than previously thought. Surgery is the preferred mode of therapy. Chemotherapy has only modest success in this entity, in contrast to the excellent results in de novo germ cell tumors. Patients treated for testicular germ cell cancer need annual follow-up evaluations throughout their life due to the possibility of late relapse.

[Two cases of testicular tumors with high alpha-fetoprotein levels: a case report].

Two patients with testicular tumors whose serum alpha-fetoprotein (AFP) persisted to show an abnormally high concentration are reported. Case 1 : A 42-year-old male who had been suffering from chronic hepatitis, underwent left high orchiectomy for a left testicular tumor in 1998. Diagnosis was an authentic stage I seminoma. In 2002, chemotherapy was performed for a metastatic seminoma revealed as a solitary mass in the mediastinum by radiographic studies, and histologically confirmed to be a metastatic seminoma. Although lymph nodes were gradually reduced in size, the serum AFP and transaminase levels remained at an abnormally high concentration. The subfraction profile with lens culinaris hemagglutinin (LCA) revealed elevation of only peak 1 which implied that the chronic hepatitis was due to liver dysfunction. After a 10-month follow-up the levels of both AFP and transaminase decreased, and the patient was disease-free. Case 2: In 2002, a 30-year-old male underwent left high orchiectomy for a left testicular tumor, and histological examination revealed seminoma, immature and mature teratoma, embryonal carcinoma. The serum AFP was elevated to 45 ng/ml. Diagnosis was authentic stage I. After 2 courses of chemotherapy, the serum AFP remained at an abnormally high concentration. However, there were no new lesions. The serum AFP level was not elevated in any of the family members. The subfraction profile with LCA revealed elevation of only peak 1, which implied that there were no viable lesions. After a 24-month follow-up AFP was about 20 ng/ml and the patient was disease-free.

An unusual presentation of metastatic testicular tumour.

We report a unique case of metastatic malignant teratoma from an undescended testis which presented with acute pulmonary embolism. After chemotherapy, the undescended right testicle was resected along with a cord of non- obstructing inferior venal caval tumour which extended into the right atrium with tumour floating free within the atrium at the end of the cord of tumour. The presentation, diagnosis and treatment of testicular tumours is described and the literature pertaining to testicular tumours in military personnel reviewed.

[Positron emission tomography in oncourology].

The authors present the results of the examination of 61 patients with genitourinary space-occupying lesions, using 18F- fluorodeoxyglucose positron emission tomography (PET) in whole body mode. In all cases the diagnosis was verified morphologically. The results demonstrated high diagnostic accuracy of PET, including possibility to determine the extent of oncourological cancer. However, the method displays poor efficacy in cases of hypernephroid cancer due to low level of glycolysis in this type of tumor.

Metastatic embryonal carcinoma mimicking locally advanced non-small cell lung cancer.

A 50-year-old man with a history of smoking of 45 pack-years underwent right lower lobectomy after neoadjuvant chemoradiotherapy for locally advanced non-small cell lung cancer diagnosed on a bronchial biopsy and standard imaging examinations, including chest-abdominal contrast-enhanced computed tomography (CT) and whole-body F-18 fluorodeoxyglucose positron emission tomography/CT. Left orchiectomy was performed simultaneously to treat the slightly swollen left testis, which had remained unchanged for over five years. The thoracic tumor was proven to be in pathological complete remission and the testicular lesion was pathologically diagnosed as an embryonal carcinoma. Furthermore, a pathological reevaluation of the preoperative bronchial biopsy specimen revealed the lung tumor to be a metastatic embryonal carcinoma.

Retinoid targets in cancer therapy and chemoprevention.

The retinoids are natural and synthetic derivatives of vitamin A. These cancer therapeutic and chemopreventive agents exert anti-proliferative, differentiation-inducing, pro-apoptotic and other biological effects. The retinoids act through nuclear retinoid receptors to activate target genes that signal retinoid biological effects. Direct retinoid targets contain retinoid responsive elements in their promoters, are directly regulated by retinoids and reproduce retinoid biological effects once introduced into a responsive cell context. Through studies conducted in in vitro models, a proteolytic mechanism was linked to retinoid induced tumor cell differentiation and chemopreventive effects. Retinoid treatments can activate the proteasome-dependent degradation pathway. In acute promyelocytic leukemia (APL), all-trans-retinoic acid (RA) can also trigger degradation of the oncogenic protein, PML-RARalpha. Microarray analysis revealed involvement of an E1-like ubiquitin-activating enzyme, UBE1L, in this induction. Retinoid chemopreventive activity in human bronchial epithelial cells was linked to triggering of G(1) cell cycle arrest, concomitant growth suppression, and a decline in expression of G(1) cyclins. This can engage proteasome-dependent cyclin degradation, causing G(1) arrest and this permits repair of genomic DNA damage. The epidermal growth factor receptor (EGFR) was also identified as a retinoid target. Retinoids exert diverse biological effects. Different retinoid target genes likely trigger distinct effects. Identification of target genes is the next step towards a molecular understanding of mechanisms of retinoid response or resistance in cancer therapy and chemoprevention.

The pathology of late recurrence of testicular germ cell tumors.

A total of 91 men had histologically documented late recurrences of testicular germ cell tumors characterized by a complete response to treatment with a subsequent disease-free interval of at least 2 years and no evidence of a second primary lesion. Ninety percent of the patients for whom information was available received chemotherapy shortly after their initial diagnosis of testicular germ cell tumors; most of the other patients were known to have stage I disease initially. Overall, 60% of patients had teratoma in their late recurrences, including 20 patients (22%) in whom teratoma was the only element. Thus, teratoma was the most common type of neoplasm in late recurrences. Excluding teratoma coexisting with other types of neoplasms, yolk sac tumor was the most frequent type of tumor in patients with late recurrence. It occurred in 47% of patients, either alone or with teratoma, another nonteratomatous germ cell tumor type, or a "nongerm cell malignant tumor." Unusual types of yolk sac tumor, including glandular, parietal, clear cell, and pleomorphic patterns, were seen frequently in late recurrences and often raised differential diagnostic problems with "nongerm cell" carcinomas. A smaller number of late recurrences consisted of other types of neoplasms. Twenty percent of patients with late recurrence had a nonteratomatous germ cell tumor other than yolk sac tumor, either alone, with yolk sac tumor, or with a "nongerm cell malignant tumor." Most of these nonteratomatous germ cell tumors other than yolk sac tumor were embryonal carcinoma, although rarely seminoma and choriocarcinoma were encountered. "Nongerm cell malignant tumors," including both sarcomas and carcinomas of various types, occurred in 23% of late-recurrence patients, either alone or with a nonteratomatous germ cell tumor. Late recurrences were seen in many different sites in these patients, including the retroperitoneum, abdomen, pelvis, liver, mediastinum, lung, bone (femur, vertebra, and rib), lymph nodes outside the retroperitoneum and mediastinum (supraclavicular, neck, and axillary regions), scrotum and inguinal regions, adrenal gland, chest wall, and buttocks. Follow-up data were available for 79 of the 91 patients studied. Duration of follow-up ranged from 2 months to 13 years after the patient's first late recurrences; the mean length of follow-up was 4.8 years. Patients whose late recurrences consisted of teratoma only had the most favorable outcomes, with 79% having no evidence of disease at last follow-up. Patients whose late recurrences consisted of pure "nongerm cell malignant tumor" or pure germ cell tumor (yolk sac tumor or other types) had a much worse prognosis: Only 36% to 37% were alive with no evidence of disease. Patients with two different types of nonteratomatous malignancies in their late recurrences had a dismal clinical course: Only 17% with both yolk sac tumor and other nonteratomatous germ cell tumor had no evidence of disease, whereas no patient with both nonteratomatous germ cell tumor and "nongerm cell malignant tumor" was disease free. Late recurrences consisting of teratoma alone often have a favorable outcome, but the prognosis in all other patients is poor. Furthermore, late recurrence is not likely to respond to chemotherapy and is best treated by surgical excision when possible.

Alterations in tumorigenicity of embryonal carcinoma cells by IGF-I triple-helix induced changes in immunogenicity and apoptosis.

IGF-I antisense gene therapy has been applied successfully to animal models of glioma, hepatoma and teratocarcinoma. The antisense strategy has shown that tumor cells transfected with vectors encoding IGF-I antisense RNA lose tumorigenicity, become immunogenic and are associated with tumor specific immune response involving CD8+ lymphocytes. An IGF-I triple helix approach to gene therapy for glioma was recently described. The approach we have taken is to establish parameters of change using the IGF-I triple helix strategy. PCC-3 embryonal carcinoma cells derived from murine teratocarcinoma which express IGF-I were used as a model. The cells were transfected with vector which encodes an oligoribonucleotide that forms RNA-IGF-I DNA triple-helix structure. The triple-helix stops the production of IGF-I. Cells transfected in this manner underwent changes in phenotype and an increase in MHC-I and B-7 cell surface molecules. They also showed enhancement in the production of apoptotic cells (60-70%). The "triple helix" transfected cells lost the ability to induce tumor when injected subcutaneously in syngeneic 129 Sv mice. When co-transfected in vitro with expression vectors encoding both MHC-I and B-7 cDNA in antisense orientation, the "triple-helix" transfected cells were down-regulated in expression of MHC-I and B-7 and the number of apoptotic cells was significantly decreased. Injection of the doubly co-transfected cells into 129 Sv mice was associated with induction of teratocarcinoma. Comparison between antisense and triple-helix transfected cells strategies showed similar immunogenic and apoptotic changes. The findings suggest that triple-helix technology may offer a new clinical approach to treatement of tumors expressing IGF-I.