High CC chemokine receptor 7 expression improves postoperative prognosis of lung adenocarcinoma patients.

BACKGROUND: Chemokines and chemokine receptors not only have significant roles in cancer metastasis and tumorigenesis but also act as antitumour agents. The interaction between the Crk-like adaptor protein (CrkL), which is encoded by the CRKL gene, and non-receptor tyrosine kinase c-ABL is reported to transform many cells into malignant cells. We examined the effects of CC chemokine receptor 7 (CCR7), CCR7 ligands and CrkL and c-ABL in lung adenocarcinoma. METHODS: One hundred and twenty patients with lung adenocarcinoma were included in this historical cohort analysis. We examined CCR7 and CCR7 ligands and CrkL and c-ABL mRNA expressions in surgically resected lung adenocarcinoma specimens and evaluated their contribution to prognosis, and the relationship with epidermal growth factor receptor (EGFR) and TP53 mutations. RESULTS: High CCR7 mRNA expressions indicated better prognoses than those of the groups with low CCR7 mRNA expressions (P=0.007, HR=2.00, 95% CI of ratio: 1.22 -3.31). In lung adenocarcinoma, CrkL and c-ABL mRNAs were related to CCR7 mRNA expression (P<0.0001). CrkL and c-ABL mRNA expressions were influenced by EGFR mutations. A high expression of CCL19 was a good prognostic factor of lung adenocarcinoma. CONCLUSION: We propose that CCR7 and CCL19 are clinically good prognostic factors and that CCR7 is strongly related to CrkL and c-ABL kinase mRNA expression in lung adenocarcinoma.

Unexpected serum level of vancomycin after oral administration in a patient with severe colitis and renal insufficiency.

OBJECTIVE: To report a case in which the serum concentration of vancomycin (VCM) reached the supratherapeutic range following oral administration in a patient with severe pseudomembranous colitis and renal insufficiency. CASE SUMMARY: A 65-year-old, 70 kg weighing man with severe acute pancreatitis and acute renal failure was subjected to continuous hemodiafiltration (CHDF). CHDF could only be performed intermittently because of the unstable circulation dynamic of this patient. After admission, intravenous VCM therapy was initiated. Thereafter, oral VCM administration was begun (0.5 g every 6 h). Despite the discontinuation of intravenous VCM after the first 2 days of oral VCM, the serum VCM concentration increased gradually to 49.8 mg/l over a period of 2 weeks from the initiation of oral administration (34.4 mg/l). Based on pharmacokinetic analysis, the bioavailability of VCM was estimated to over 33%. Autopsy findings indicated broadly distributed necrosis on the lamina propria of the mucosa throughout all parts of the intestine below the duodenum. DISCUSSION: This case indicates necessity of the careful monitoring after oral high-dose VCM administration in a patient with a broadly distributed necrosis and renal insufficiency. CONCLUSIONS: TDM should be considered according to renal function, the severity of enteritis and the total dosage of oral VCM administration.

A human protein with sequence similarity to Drosophila mastermind coordinates the nuclear form of notch and a CSL protein to build a transcriptional activator complex on target promoters.

Mastermind (Mam) has been implicated as an important positive regulator of the Notch signaling pathway by genetic studies using Drosophila melanogaster. Here we describe a biochemical mechanism of action of Mam within the Notch signaling pathway. Expression of a human sequence related to Drosophila Mam (hMam-1) in mammalian cells augments induction of Hairy Enhancer of split (HES) promoters by Notch signaling. hMam-1 stabilizes and participates in the DNA binding complex of the intracellular domain of human Notch1 and a CSL protein. Truncated versions of hMam-1 that can maintain an association with the complex behave in a dominant negative fashion and depress transactivation. Furthermore, Drosophila Mam forms a similar complex with the intracellular domain of Drosophila Notch and Drosophila CSL protein during activation of Enhancer of split, the Drosophila counterpart of HES. These results indicate that Mam is an essential component of the transcriptional apparatus of Notch signaling.

Colony-stimulating factor 1 expression is down-regulated during the adipocyte differentiation of H-1/A marrow stromal cells and induced by cachectin/tumor necrosis factor.

We isolated clonal sublines of the established mouse marrow stromal cell line, H-1. These clonal sublines underwent differentiation into adipocytes in various degrees. One subline, H-1/A, underwent adipocyte differentiation after confluence, while another subline, H-1/D, did not differentiate. In H-1/A cells, the 4.5- and 2.5-kb major mRNA species of colony-stimulating factor 1 (CSF-1) were expressed before differentiation and were down-regulated at a posttranscriptional level during the differentiation of H-1/A cells. The down-regulation of the CSF-1 gene was not a result of arrested cellular growth, because no down-regulation was detected in the nondifferentiating sister line, H-1/D. This down-regulation appeared to be an early event in differentiation. Cachectin/tumor necrosis factor transiently induced the expression of CSF-1 and inhibited the differentiation of H-1/A cells into adipocytes. This induced expression of CSF-1 was due to an increased rate of transcription.

Effect of direct cell-to-cell interaction between the KM-102 clonal human marrow stromal cell line and the HL-60 myeloid leukemic cell line on the differentiation and proliferation of the HL-60 line.

Hematopoietic cellular interaction was investigated in a coculture of the human clonal marrow stromal line, KM-102, and the myeloid leukemia cell line, HL-60. In the coculture, a large number of HL-60 cells remained in the supernatant but some of them became firmly attached to KM-102 cells. The attached HL-60 cells showed little positive reaction in the NBT test when the culture was supplemented with 10(-9) to 10(-7) M 1 alpha, 25-dihydroxyvitamin D3. In contrast, differentiation in the supernatant HL-60 cells was strikingly responsive to the agent in a dose-dependent way. Furthermore, the complete inhibition was observed in the incorporation of [3H]thymidine into the attached HL-60 cells with autoradiography, but 23.6% of the supernatant cells moderately incorporated [3H] thymidine into their nuclei. There was no attachment between HL-60 cells and stromal cells from human thymus and lymph node, or between lymphocytic leukemia cells and marrow stromal cells. These results indicate that there is direct cellular interaction between myeloid leukemic cells and marrow stromal cells which modulates the proliferation and differentiation of the myeloid leukemic cells. This modulation by marrow stromal cells is more strongly affected by this interaction than by exogenously added differentiation-inducing agents. Apparently marrow stromal cells produce a definitive milieu for the proliferation and differentiation of myeloid leukemic cells.

Quantitative analysis of the two macrophage colony-stimulating factor mRNA expressed in a human stromal cell line by reverse transcription-polymerase chain reaction (RT-PCR).

We established a quantitative analysis system for 4.0 kb and 1.6 kb macrophage colony-stimulating factor (M-CSF) mRNA, using reverse transcription-polymerase chain reaction. Using this system, we performed quantitative analysis of the two mRNAs expressed in the human stromal cell line, KM102, in the resting condition and when stimulated by various concentrations of interferon-gamma (IFN-gamma). The expression of 1.6 kb M-CSF mRNA was more efficiently stimulated by IFN-gamma than that of 4.0 kb M-CSF mRNA. The alternative splicing of a single M-CSF gene has been shown to generate several M-CSF proteins with different localization; we believe that molecular analysis of the transcription products by this system is important to better understand the physiological significance of the different species of M-CSF derived from each mRNA.

Differentiation of human hematopoietic cells increases expression of a gene transferred by a retroviral vector.

To study expression of a retroviral vector in human hematopoietic lineages, two established human hematopoietic cell lines (HL60 and K562) and a human adherent stromal cell line (KM101) were infected with the vector pZIP-SV(X). Expression of the transferred neomycin resistance gene (neor) of pZIP-SV(X) was evaluated as the ability of the cells to form colonies (greater than 50 cells) in an agar assay in the presence of the neomycin analogue, G418. After infection, all three cell lines produced colonies resistant to G418. The level of neor mRNA in separate colonies was analyzed by Northern blot analysis. The neor gene transferred by the vector pZIP-SV(X) was expressed in both human hematopoietic and stromal cell lines. In addition, primary adherent human stromal cells infected with pZIP-SV(X) grew in the presence of G418. To determine if differentiation of hematopoietic cells affects expression of the retroviral vector, HL60 cells infected with pZIP-SV(X) were induced to differentiate, and the level of neor mRNA measured. The amount of neor mRNA increased when HL60 cells were induced to differentiate along the granulocytic pathway. Conversely, when HL60 cells were induced toward monocytoid differentiation (TPA), the level of neor mRNA did not significantly increase. We conclude that the neor gene transferred by a retroviral vector, pZIP-SV(X), is functionally expressed. In addition, expression of the transferred neor gene is regulated during myeloid differentiation of HL60 cells.

A burst-promoting activity derived from the human bone marrow stromal cell line KM-102 is identical to the granulocyte-macrophage colony-stimulating factor.

Recently, several human bone marrow stromal cell lines have established and produced hematopoietic growth factors. One of these factors, a burst-promoting activity (BPA), was purified from 6 liters of serum-free conditioned medium cultured from stromal cell line KM-102, which was stimulated by phorbol myristate acetate (PMA) and calcium ionophore A23187. This stimulation induced 60 times more production of BPA than the unstimulated control culture. BPA was purified 4000-fold by sequential fractionation using ammonium sulfate precipitation, anion-exchange and lentil lectin affinity chromatographies, high performance gel filtration chromatography, and reversed phase high performance liquid chromatography. Purified BPA gave a single broad band of protein with a molecular weight of approximately 18 kd, as assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The concentration required for half maximal growth of early erythroid colonies was estimated as 10 pg/ml or 0.6 pM. At a higher concentration (125 pg/ml) this factor also stimulates the growth of granulocyte, macrophage, and eosinophil colonies in agar culture. The profile of amino acid composition is very similar to that of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) deduced from its complementary DNA sequence. The result of amino-terminal sequence analysis strongly suggests that the purified material consists of GM-CSF and tetrapeptide-deleted GM-CSF. Moreover, antibody against GM-CSF completely neutralized the biological activities of this factor. These results indicate that the human bone marrow stromal cell line secretes GM-CSF as a burst-promoting activity and GM-CSF may play a significant role in the interaction between stem cells and stromal cells in the hematopoietic microenvironment.

Gap-junctional communication of bone marrow stromal cells is resistant to irradiation in vitro.

Bone marrow is one of the most radiosensitive organs. Irradiation causes a marked decrease in the total number of hematopoietic cells in the bone marrow. The reticular meshwork structure of marrow stromal cells, however, is relatively resistant to irradiation. Unimpaired stromal cell structure has been thought to be a prerequisite for the repopulation of hematopoietic cells during recovery from the effects of irradiation. The reticular framework is maintained by cell adhesion apparatuses such as gap junctions. The in vitro radiobiologic survival values of a cloned stromal cell line, H-1/A, were studied (ñ = 1.8, D0 = 138 cGy). Radiation doses of up to 4000 cGy had no detectable effects on the production of colony-stimulating factor 1. H-1/A cells communicate with each other via gap junctions as determined by the sensitive dye-transfer method. Gap-junctional communication between H-1/A cells was resistant to different levels of irradiation (500 to 10,000 cGy), but it was lost during adipocyte differentiation of H-1/A cells. Marrow stromal cells, which are important in the recovery of hematopoiesis, seemed capable of coordination with each other through gap junctions even when exposed to radiation.

Novel functions and cellular interaction of human lymphoid stromal cells with lymphoid cell lines in vitro.

Lymphoid stromal (SG) cells have been isolated from the lymph node of a patient with malignant lymphoma, and characterized by positive reaction with a monoclonal antibody against the T-zone stromal cells in human lymph nodes. B-acute lymphoblastic leukemia (BALL) cells showed prominent emperipolesis toward SG cells when they were cocultured, whereas T-acute lymphoblastic leukemia (TALL) cells attached firmly to the surface of SG cells. Autologous peripheral B and T cells behaved, respectively, in the same way as BALL and TALL cells. Both BALL and TALL cells while directly interacting with the SG cells were completely inhibited from incorporating [3H]thymidine, although radioactive grains were observed in 16.4%-12.4% of supernatant BALL and 13.8%-13.0% of supernatant TALL cells in each coculture. Furthermore the media conditioned by SG cells significantly increased the incorporation of [3H]thymidine into the TALL cells as much as 190% of the control. These results indicate that SG cells undergo tissue-specific cellular interactions with B- and T-lymphoid cell lines but not with a myeloid cell line, and they can modify their growth by two distinct mechanisms. SG cells proved to be very useful in studying the effect of the lymphoid microenvironment on the proliferation of lymphocytes in vivo.

Activation of mitogen-activated protein kinase through alpha5/beta1 integrin is required for cell cycle progression of B progenitor cell line, Reh, on human marrow stromal cells.

OBJECTIVE: Attachment to bone marrow (BM) stromal cells is crucial for the normal growth and development of B-cell progenitors (pro-B). However, the molecular mechanisms by which contact facilitates the proliferation of pro-B cells are not completely understood. This study was performed to investigate this interaction. MATERIALS AND METHODS: A model pro-B cell line (Reh) and a human BM stromal cell line (KM102) were used. Flow cytomery was used for cell cycle analysis. Western Blotting and immunoprecipitation were utilized to examine the levels of cyclin-dependent kinase (cdk) and p27(Kip1). RESULTS: Attachment to both KM102 and normal BM stromal cells significantly promoted the growth of Reh cells. Pretreatment of Reh cells with anti-integrin beta1 or alpha5 monoclonal antibody (mAb), but not alpha4 or ICAM-1 mAb, abrogated this enhancement of proliferation. Furthermore, stroma attachment resulted in shortening of the G(1) phase of cell cycle, significant increases cdk2 activity, degradation of cdk inhibitor p27-GST protein, and decrease in levels of p27(Kip1) protein. In addition, solid-phase cross-linking of alpha5 via immobilized antibody also resulted in extracellular signal-regulated (ERK)-2 kinase phosphorylation, increase in cdk2 activity, decrease in levels of p27(Kip1) protein, and enhanced proliferation that was inhibited by treatment with PD98059, a specific ERK inhibitor. CONCLUSION: Integrin alpha5beta1-mediated stroma contact promotes the proliferation of B-cell progenitors through the activation of ERK-2, which in turn modulates cell cycle regulation machinery including induction of cdk2 activity and degradation of p27(Kip1) and contributing to acceleration of the G(1) phase of cell cycle progression.

Alteration of the proteoglycan form of macrophage colony-stimulating factor produced by a human stromal line stimulated by tumor necrosis factor-alpha.

Immunoblot analysis of macrophage colony-stimulating factor (M-CSF) in KM 102 cell-conditioned medium showed the presence of two M-CSF molecular types, one being 85-kd M-CSF, the other a proteoglycan form (PG-M-CSF) carrying a chondroitin sulfate chain of variable length. When KM 102 cells were stimulated by TNF-alpha, they produced more M-CSF than that produced in unstimulated condition, in which PG-M-CSF had a shorter chondroitin sulfate chain. Although PG-M-CSF has binding affinity for type V collagen, the PG-M-CSF with the shorter chondroitin sulfate chain shows lower affinity. This spreads in type V collagen-containing agarose gel more easily than does PG-M-CSF with a longer chondroitin sulfate chain.

Tissue inhibitor of metalloproteinases from human bone marrow stromal cell line KM 102 has erythroid-potentiating activity, suggesting its possibly bifunctional role in the hematopoietic microenvironment.

In this study, we demonstrated that tissue inhibitor of metalloproteinases (TIMP) produced by human bone marrow stromal cell line KM-102 had erythroid-potentiating activity (EPA) which stimulates the proliferation of erythroid progenitor cells. We, then, propose a scheme for the bifunctional role of TIMP/EPA in hematopoietic microenvironment, that is, the maintenance of the integrity of bone marrow matrix and the proliferation of erythroid progenitor cells proceeding on the matrix.

Gamma-irradiation response of cocultivated bone marrow stromal cell lines of differing intrinsic radiosensitivity.

There is evidence for differences in the gamma-irradiation response of different cellular lineages within the bone marrow microenvironment. We previously reported that heterogeneity is demonstrable in the gamma-irradiation response of five clonal stromal cell lines, derived from one human bone marrow specimen, despite morphological, histochemical, cytogenetic, and functional similarity. In the present study we tested whether one stromal cell line could affect the intrinsic radiosensitivity of another. Two clonal stromal cell lines, which display distinct gamma-irradiation responses relative to dose rate were used: KM 101, which shows the same radiosensitivity at a low dose rate of 5 cGy/min (LDR) and a high dose rate of 120 cGy/min (HDR) and KM 104 which shows significant gamma-irradiation resistance at LDR. To facilitate the study of the gamma-irradiation response of each cell line during cocultivation, we derived stable subclones of each, expressing the transfected neomycin resistance (neo-r) gene, which confers resistance to the neomycin analog: G 418. Introduction of the neo-r gene did not alter cell lines radiosensitivity. The results show that cocultivation of stromal cell lines before, during, and after gamma-irradiation induces changes in repair of radiation-induced damage, with a dominant effect of a resistant cell line at LDR. In fact, the radiation survival curves of cocultivated stromal cell lines were always characteristic of KM 104, and a dose rate effect was observed, even when KM 101 was present in large excess. Moreover, our results are consistent with preferential killing of the more radiosensitive stromal cell line: both LDR and HDR Do values of the neo-r KM 101, cocultivated with the parent KM 104 for 24 hr before, and during gamma irradiation were significantly lower compared to the neo-r subclone irradiated alone. The LDR Do value of the neo-r KM 104 cocultivated for 24 hr before, and during gamma irradiation with excess of parent KM 101, was significantly higher, compared to the neo-r cells irradiated alone.

Radiosensitivity of permanent human bone marrow stromal cell lines: effect of dose rate.

In contrast to the dose-rate independent X ray killing observed with human bone marrow hematopoietic stem cells, bone marrow adherent stromal cells from the same fresh marrow harvests demonstrate increased radiation resistance at low dose rate (LDR) (5 cGy/min), compared to high dose rate (HDR) irradiation (120-200 cGy/min). Physiologic changes observed in plateau phase bone marrow cells after LDR irradiation in vivo and in vitro suggested that marrow stromal cells might be heterogeneous in LDR irradiation repair. Five permanent clonal bone marrow stromal lines were derived from a single human marrow donor. Each cell line was positive for markers of fibroblasts including: immunohistochemically detectable fibronectin, collagen, acid phosphatase, and nonspecific esterase, and was negative for Factor VIII, alkaline phosphatase, lysozyme and several markers of marrow macrophages. The x-irradiation survival curve of each cell line was determined at LDR and HDR in vitro. Cell lines KM102, KM103, KM104, and KM105 each demonstrated a significant (p less than .05) increase in radioresistance at LDR (D0 = 142, n = 2.9; D0 = 131, n = 2.5; D0 = 145, n = 2.1 and D0 = 127, n = 2.1 respectively) compared to HDR: (D0 = 111, n = 2.1; D0 = 94, n = 3.5; D0 = 99, n = 3.5 and D0 = 95, n = 2.1 respectively). In contrast, cell line KM101 demonstrated no significant change in radiosensitivity relative to dose rate at LDR (D0 = 113, n = 3.3) compared to HDR, D0 = 114, n = 3.3. Cell line KM101 was more supportive than the other lines of cocultivated hemopoietic cells in vitro. Subclones of KM101 and KM104 selected by retroviral vector transfer of the neor gene for growth in the antibiotic neomycin-analogue G418, maintained the stably associated radiobiologic properties of each parent clonal line. These data indicate significant heterogeneity in the LDR irradiation response of clonal stromal cell lines derived from human bone marrow.

A case of massive true thymic hyperplasia with non-Hodgkin's lymphoma.

A case of massive true thymic hyperplasia with non-Hodgkin's lymphoma of the mediastinum is reported in a 14-year-old boy. Computed tomographic scan of the chest showed a mass of the anterior mediastinum and conspicuous swelling of the lymph nodes in the upper and lower mediastinum. They were grossly resected. The tumor of the anterior mediastinum was histologically diagnosed as true thymic hyperplasia. All of the mediastinal lymph nodes were diagnosed as non-Hodgkin's lymphoma, diffuse, mixed small and large cell type.

Clinicopathological evaluation of the Revised European-American Classification of Lymphoid Neoplasms (REAL) in Japan.

After the publication of a Revised European-American Classification of Lymphoid Neoplasms (REAL classification) in 1994, there have been reports from Europe and America regarding its practical utility and clinical significance. However, no studies have been published from Eastern countries including Japan. It has been well recognized that the distribution of malignant lymphoma in Japan is quite different from that seen in Western countries. In addition, some new entities have also been described in the REAL classification. Therefore, it seems important to examine its practical utility and clinical significance in Japan. Of the 579 cases reviewed, approximately 68% were B-cell non-Hodgkin's lymphoma (NHL) followed by 27% T-cell lymphomas. Hodgkin's disease (HD) comprised only 5% of all cases, making the ratio of NHL to HD 20.6. The most common type was diffuse large B-cell lymphoma which represented about 37% of all cases. Peripheral T-cell lymphomas, unspecified (PTCL), occurred in 15% whereas marginal zone B-cell lymphoma followed (14.9%). However, follicle center lymphoma (FCL) was less common (4.4%) as has been previously reported. We evaluated the clinical significance of the new REAL classification in 244 cases. International Prognostic Index (IPI) was a powerful predictor of survival (p<0.0001), and the immunophenotype was significant (p<0.05). Furthermore, here, we also attempt to establish a prognostic scheme based on the histologic type. In conclusion, the REAL classification appears to be useful and clinically significant in Japan.

Immunoglobulin heavy chain variable region (VH) genes of B cell chronic lymphocytic leukemia cells from lymph nodes show somatic mutations and intraclonal diversity irrespective of follicular dendritic cell network.

We analyzed the immunoglobulin heavy chain variable region (VH) gene in 4 Japanese cases of B cell chronic lymphocytic leukemia (B-CLL) with enlarged lymph nodes to clarify the presence of somatic mutations and intraclonal diversity. We also attempted to determine the role of the follicular dendritic cell (FDC) network in some proliferation centers, where tumor cells are mitotically active. Immunohistochemical studies revealed that all 4 cases showed the typical immunophenotype: CD5+, CD23+, IgM+ and IgD+. DNA was extracted from paraffin sections (lymph node) and rearranged VH gene was amplified by PCR. All but one exhibited a moderate number of somatic mutations, with percentages ranging from 4.1 to 9.5, and one of which indicated the effect of antigen selection on its VH gene. Multiple clone analysis of whole tissues showed intraclonal diversity in one case, whose VH gene carried a somatic mutation but the effect of antigen selection was not apparent. We further examined microdissected tissues to elucidate the relationship between FDC network and VH gene status in 2 cases. In one case, intraclonal diversity was not apparent irrespective of FDC network, however, both tumor cells around the FDC network and those apart from the FDC showed signs of intraclonal diversity in another case, suggesting that intraclonal diversity was not related to the FDC network in B-CLL. Here we demonstrate that some cases of B-CLL involved in lymph node carried mutated VH genes and showed intraclonal diversity like the tumor cells in the peripheral blood. However, the significance of the FDC network in the proliferation center still remains to be resolved.

Expression of cell cycle regulating proteins in an unusual transformation of mantle cell lymphoma.

We describe here two patients with mantle cell lymphoma (MCL) who after a few years, developed to the diffuse large cell lymphoma (DLCL) (anaplastic centrocytic lymphoma) growing in a diffuse sheets without the classical MCL component. In both the initial and second biopsy specimens, in each case, tumor cells were positive for cyclin D1, sIgM, sIgD, and CD5, but were negative for CD10 and CD23. In a study of immunoglobulin heavy chain (IgH) gene rearrangement, using the polymerase chain reaction (PCR) method, the products obtained from each paired biopsy tissue sample were the same size, and in one case had an identical sequence to the non-mutated VH gene. Immunohistochemistry was used to examine the expression of p53, p27Kip1 and cyclin E. Interestingly, there was clear overexpression of p53 protein in case 1 but not in case 2, compared with other typical MCL cases. The expression of p27Kip1 in the second biopsies of each case was decreased compared with those in the initial biopsies. In case 2, however, p27Kip1 was clearly expressed in the first and second biopsies, in contrast to other typical MCL cases. Thus these 2 cases demonstrate not only that the variant form of MCL may arise de novo, but also that MCL may transform to DLCL at the time of relapse. Although the mechanism of tumor progression/transformation is still poorly understood, the overexpression of p53 or p27Kip1 may be linked to a cellular mechanism involved in the development of the variant form of MCL.

Extraneural metastasis of choriocarcinomatous element in pineal germ-cell tumor. Case report.

A case of pineal germ-cell tumor producing human chorionic gonadotropin (HCG) and alpha-fetoprotein (AFP) is reported in a 23-year-old man. Extraneural metastasis developed during a course of combined chemotherapy after radiation therapy. Postmortem examination revealed that the metastatic pulmonary tumor was a choriocarcinoma, producing only HCG.