Combination radiofrequency ablation and local injection of the immunostimulant bacillus Calmette-Guérin induces antitumor immunity in the lung and at a distant VX2 tumor in a rabbit model

PURPOSE

To evaluate whether the combination of radiofrequency (RF) ablation and local injection of the immunostimulant Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces systemic antitumor immunity.

MATERIALS AND METHODS

Japanese White rabbits with lung and auricle VX2 tumors were randomized into three groups: control (n = 8; no treatment), RF ablation only (n = 8; RF ablation to the lung tumor), and RF ablation with local BCG injection into the lung tumor (n = 8). Treatments were performed 1 week after tumor implantation. Survival was evaluated with Kaplan-Meier method and log-rank test. Weekly mean volume and specific growth rate (SGR) of auricle tumors were calculated, and comparisons were made by Mann-Whitney test.

RESULTS

Median survival of control, RF-only, and RF/BCG groups were 23, 41.5, and 103.5 days, respectively. Survival was significantly prolonged in the RF-only and RF/BCG groups compared with the control group (P = .034 and P =.003, respectively), but no significant difference was found between the RF-only and RF/BCG groups (P = .279). Only in the RF/BCG group was mean auricle tumor volume decreased 5 weeks after implantation. No significant difference in SGR was found between the control and RF-only groups (P = .959), but SGR in the RF/BCG group was significantly lower than in the control group (P = .005).

CONCLUSIONS

The combination of RF ablation and local injection of BCG resulted in distant tumor suppression compared with the control group, whereas RF ablation alone did not produce this effect. Therefore, the combination of RF ablation and local injection of BCG may induce systemic antitumor immunity.

Primary Cultures of Human Vestibular Schwannoma

OBJECTIVE

To establish primary vestibular schwannoma (VS) cultures that selectively favor the growth of schwannoma cells.

BACKGROUND

The lack of a suitable in vitro model of human VS cells has directly limited the progress of research on tumorigenesis and therapy. The problems of establishing pure VS culture include control of fibroblast proliferation. Current efforts to extend VS cell life span using viral oncogenes, by conferring the ability to proliferate in vitro, will yield cells intrinsically different from in vivo VS tumors. Much more desirable is the ability to culture VS cells without cellular transformation.

METHODS

Tumor specimens from 17 patients were processed for cell culture and grown at 37 degrees C with 5% CO2 and 100% humidity. Key modifications limiting fibroblast proliferation included using selective medium without L-valine, supplemented by Nu-Serum for at least a week; the use of cytosine arabinoside to kill contaminating fibroblasts; and using the Dulbecco modified medium, supplemented with brain-derived neurotrophic factor and 10% fetal calf serum after the initial serum-free period.

RESULTS

Twelve of 17 VS were successfully cultured. The presence of schwannoma cells and the absence of fibroblasts were confirmed immunohistochemically using S100 and CD90 markers, respectively. Scanning and transmission electron microscopy demonstrated typical spindle-shaped cells and the presence of "fibrous long-spacing collagen."

CONCLUSION

We describe a method for obtaining short-term, essentially fibroblast-free, primary VS cultures. Such pure VS cultures, retaining in vivo characteristics, are extremely useful as an in vitro model to study the pathobiology of schwannoma cells.

Spindle cell carcinoma of the external auditory meatus with intracranial extension: histological, immunohistochemical and electron microscopic evaluation

We present a case of squamous spindle cell carcinoma of the external auditory meatus in a 38-year-old man. The tumour was extended to the inner ear, the temporal bone, the middle cranial fossa and the meningo-cerebral tissue. The surgical intervention of temporo-occipital craniotomy removed most of the neoplasia. At pathologic examination, the tumour showed an undifferentiated spindle cell pattern. Immunohistochemistry with a large antibody panel found a weak positivity only to EMA. The diagnosis was made when the electron microscopy showed rare junctional structures and tonofilaments.

De novo CD5-positive diffuse large B-cell lymphoma of the temporal bone presenting with an external auditory canal tumor

We report a 74-year-old woman with primary CD5-positive diffuse large B-cell lymphoma (DLBCL) of the temporal bone. The patient was admitted because of a mass in the left external auditory canal. She was treated with eight courses of CEOP therapy (rituximab was added from the sixth course) followed by radiotherapy of 40 Gy, and complete remission was achieved. The occurrence of malignant lymphoma in the temporal bone, which is an extremely unusual site, may have depended on the peculiarity of CD5-positive DLBCL.

Immunoblotting analysis of schwannomin/merlin in human schwannomas

HYPOTHESIS

Absent or reduced expression of schwannomin/merlin is associated with tumorigenesis of sporadic schwannomas.

BACKGROUND

The neurofibromatosis type 2 (NF2) gene frequently is mutated in sporadic vestibular schwannomas. The protein product of the NF2 gene is called schwannomin or merlin. Little is known about the mutated forms of schwannomin/merlin present in schwannomas.

METHODS

To investigate further the role of schwannomin/merlin in schwannoma tumorigenesis, immunoblotting experiments were performed. Antischwannomin/merlin-specific antibody that recognizes amino terminus of the protein was used to determine the expression levels of schwannomin/merlin in 16 sporadic vestibular schwannomas, 1 NF2-related vestibular schwannoma, and 5 spinal schwannomas.

RESULTS

The antibody detects a protein of approximately 66 kDa in the Triton X-100-insoluble fraction of tumors. The expression of schwannomin/merlin was severely reduced, <35% of control, in 11 (50%) of 22 sporadic schwannomas and in 1 NF2-related vestibular schwannoma. The intensity of 66-kDa schwannomin/merlin band was moderately reduced, from 35-60%, in 7 (32%) of 22 schwannomas compared to the expression levels found in the human brain. Truncated forms of schwannomin/merlin were identified in three tumors with moderately reduced schwannomin/merlin.

CONCLUSIONS

These results provide new evidence that inactivation of schwannomin/merlin is an important factor in tumorigenesis of sporadic schwannomas.

Immunohistochemical and ultrastructural investigation of the human vestibular dark cell area: roles of subepithelial capillaries and T lymphocyte-melanophage interaction in an immune surveillance system

BACKGROUND

The aim of the present study was to morphologically characterize the structure of the subepithelial blood vessels in the dark cell area of the human vestibular organs, and to determine whether immunocompetent cells such as macrophages and lymphocytes could be found around these small blood vessels.

MATERIALS AND METHODS

All 31 surgical specimens (semicircular canals and utricles) were obtained from patients with vestibular schwannoma. Formalin fixed specimens were stained with hematoxylin and eosin (H&E), and with antibodies to von Willebrand Factor (vWF), leukocyte common antigen (LCA), and UCHL-1, and were examined with light microscope. Specimens fixed with glutaraldehyde were examined with a transmission electron microscope (TEM).

OBJECTIVES

Subepithelial blood vessels stained positive for vWF. By TEM observation, these blood vessels were observed to be capillaries that consisted of non-fenestrated endothelium, occasional pericytes, and a basement membrane. They were usually accompanied by melanophages with a number of secondary lysosomes containing phagocytosed degraded melanosomes and lipid droplets. Moreover, melanocytes and their cell processes directly surrounded these subepithelial capillaries. The fact that cells which were positively stained with LCA and UCHL-1 were present both in the intra- and subepithelial layer of the specimens, and that by TEM the intra- and subepithelial mononuclear cells with a lymphoid appearance had clustered dense bodies in their cytoplasm, suggested that they were a population of T lymphocytes.

CONCLUSIONS

Results suggested the possibility of a T lymphocyte-melanophage (macrophage) interaction, both originating from and harbored around subepithelial capillaries, which suggests the presence of an immune surveillance system in the human vestibular organs.

[Basal cell and basosquamous carcinomas of the external ear. Immunohistochemical study]

Malignant neoplasms of the external ear are difficult diseases of the cervical-facial area to study clinically and therapeutically. The most frequent malignant histological patterns are spinocellular and basocellular carcinomas. Melanomas, basosquamous or "metatypical" carcinomas are less frequent. The latter have a transition histological pattern halfway between a basocellular and spinocellular carcinoma. In our experience, some external ear neoplasms, diagnosed as basocellular, were clinically more invasive (aggressive). Therefore we studied the immunohistochemistry of operative specimens with monoclonal antibodies (MoAb) with the purpose of revaluating the diagnosis after follow-up, and of detecting unrecognized basosquamous carcinomas. We studied 4 patients (2 male and 2 female) aged between 58 and 78, examined in the period 1990-92 an a diagnosed as having an external ear basocellular carcinoma. The immunohistochemical study was carried out using anti-CEA (carcinoembryonal antigen) monoclonal antibodies, high molecular weight acid anticytokeratins (anti-AE3) and low molecular weight basic anticytokeratins (anti-AE1). Appendage origin of the neoplasms was excluded after carrying out MoAb anti-CEA tests, negative in all patients. Epithelial origin of the neoplasms were confirmed after carrying out MoAb anti-AE3 tests, positive in all patients. After carrying out MoAb anti-AE1 tests, positive in 3 patients out of 4, we reviewed the classification of 2 basocellular carcinomas out of 4. These tumors evidenced an atypical dyskeratosis and a positivity for intracellular keratinization. These aspects were not evidenced in the previous histological examinations using routine stains and could be an index of unfavourable clinical evolution of these two cases from a basocellular carcinoma toward a more aggressive basosquamous carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

[A case of ceruminous adenocarcinoma. Ultrastructural and immunohistochemical studies]

Case of ceruminal adenocarcinoma is reported. Tumor was diagnosed in advance stage, and within a month following diagnosis it caused death. Tumor started from right auditory canal, undermined the pyramidal bone and infiltrated great part of right side of base of skull, narrowing great foramen to a certain extent. Metastasizes were only the right of dura. Besides electron microscopic studies, authors performed the immune-histochemical and lectin-histochemical examination of tumor the first time.

[Lymphocytoma--a borreliosis?]

4 patients suffering from lymphocytoma had been observed for a mean of 1.75 years (13 to 21 month). The lesions were located on the ears; all patients developed regional lymphadenopathy. Two patients experienced headaches of short duration, one child showed six erythema migrans lesions, and another child had an elevated IgM level of 322 mg/dl. A tick bite was noted in one child. Indirect immunofluorescence tests revealed significantly elevated IgG or IgM antibody titers against Ixodes dammini and Ixodes ricinus spirochetes in all patients. Serological evaluation may be helpful in differentiating borrelial lymphocytoma from other pseudolymphomas.

Immunologic aspects of otologic disease: an overview

The immunologic explosion has now reached the field of otology. By having better techniques to measure the changes at cellular and molecular levels, it is now possible to devise experiments to show morphologic anatomic changes as well as functional changes. The demonstration in 1980 (M.S.) that tympanosclerosis could be induced immunologically represents a concrete advancement in immunologic thinking in conceptualization of otologic disease. In 1974, one of the authors (M.S.) published work dealing with the treatment of vasculitis of immunologic origin for sudden hearing loss. This was aimed at inhibiting the complement cascade from starting its destructive action. Recently, the immunologic challenge in animals demonstrated by changes in the inner ear was shown by one of the authors (T.J.Y.). Such changes were compatible with labyrinthine hydrops, or Meniere's disease, otosclerosis, and sensorineural hearing loss and vestibular dysfunction.

[Results of repeated IgE titre determinations for the early diagnosis of tumour recurrence in the otolaryngological area (author's transl)]

Repeated serum IgE determinations in 292 tumour patients, in parallel with clinical check-ups, show the great diagnostic significance of the serum IgE level. The IgE titre variations give an insight into the tumour-host relationship and, in particular, into the current state of activity of the tumour patients who were found to be tumour-free after specific therapy have constant serum IgE values on repeated examination. The serum IgE level declines significantly during radiotherapy and after operative therapy. Tumour recurrence or metastases cause a sharp increase in the serum IgE level already before clinical manifestations can be ascertained. Hence, this method contributes through continued immunological checks towards an early diagnosis of tumour activity.

Embryonic antigen expression on 2-acetylaminofluorene induced and spontaneously arising rat tumours

2-Acetylaminofluorene induced mammary and ear duct carcinomata and spontaneously arising mammary carcinomata and sarcomata were shown to express embryonic antigens at the cell surface by their reaction with serum from multiparous female rats. These observations with essentially non-immunogenic tumours are comparable with early findings showing that embryonic antigens are also expressed on aminoazo dye induced rat hepatomata, and sarcomata induced with 3-methylcholanthrene. Re-expression of embryonal components, therefore, may be a concomitant of neoplastic transformation.