Studies on the sensitization of animals with simple chemical compounds. 13. Sensitization of guinea pigs with picric acid.

A method of establishing regular and intense sensitivity to picric acid is described, based upon an initial sensitization by a "split-adjuvant" technique in which the intradermal injection of mycobacteria in paraffin oil precedes or follows the administration of allergen to the same sites. When subsequent contact applications of picric acid are later made, the degree of sensitivity rises in steps such that reactivity occurs in tests made with low concentrations of picric acid, in the range of 0.06-0.006% but varying somewhat from one experiment to another. This heightening of picric acid reactivity represents an anamnestic response in the area of delayed hypersensitivity. The characteristics of contact reactions to the weak allergen, picric acid, differ from those encountered with covalently binding haptens, PCI and DNCB. A slow evolution from an initial micropapular reaction to full reaction requires about 3 days, leading often to a micaceous scale, with histological evidence of vesiculation even while the reaction is still feeble, and to an infiltrate containing a significant number of polymorphonuclear leukocytes. Substitution of an emulsion of picric acid in complete Freund's adjuvant as a priming experience proved to be much less efficient. The split-adjuvant technique offers a general plan for sensitizing with weak allergens. Indeed, technically, sensitization can be acquired even when, for priming, the allergen is applied topically over intradermal depots of mycobacteria in paraffin oil. Compatibility between sensitizer and adjuvant is not required.

Potentiation of human cell-mediated and humoral immunity by low-dose cyclophosphamide.

Although cyclophosphamide (CY) is a potent immunosuppressive drug, under the proper conditions, it can potentiate immune responses as well. In past work, we have shown that administration of a commonly used oncostatic dose of CY (1000 mg/sq m) to patients with advanced cancer 3 days before sensitization with the primary antigen, keyhole limpet hemocyanin (KLH), resulted in augmentation of delayed-type hypersensitivity (DTH) but not antibody response to that antigen. The present study was performed to test the immunopotentiation of a lower dose of CY (300 mg/sq m); animal studies and studies of human lymphocytes in vitro suggested that the lower dose might be more effective. Eighteen patients with advanced metastatic cancer were alternately assigned to one of two groups. Sixteen days before CY, one group received KLH and the other group received 1-chloro-2,4-dinitrobenzene (DNCB). CY 300 mg/sq m was given as an i.v. bolus on Day 0. Three days after CY, the patients received KLH or DNCB, whichever they had not received initially. Blood was drawn for antibody titer, and skin testing was performed 14 days after administration of KLH or DNCB. In addition, skin tests to microbial recall antigens were made 2 days before and 17 days after CY. Pretreatment with low-dose CY resulted in significant augmentation of DTH to KLH; thus, the median DTH responses were: KLH alone, 10 mm; and KLH after CY, 27 mm (p less than 0.01). CY pretreatment also resulted in augmentation of the antibody response to KLH. The median total antibody titers (log2 of reciprocal of dilution) were as follows: KLH alone, less than 1; and KLH after CY, 3 (p less than 0.01). All nine CY-pretreated subjects but only 4 of 9 controls developed measurable anti-KLH antibody titers. CY pretreatment neither augmented nor suppressed the 48-hr challenge reaction to DNCB. Moreover, CY had no effect on DTH responses to the recall antigens, dermatophytin, Candida, and mumps.

Induction of cell-mediated immunity to autologous melanoma cells and regression of metastases after treatment with a melanoma cell vaccine preceded by cyclophosphamide.

There is considerable evidence in animal tumor systems that antitumor immunity is modulated by suppressor T-lymphocytes, and that the cytotoxic drug cyclophosphamide (CY) can abrogate that suppression. We measured the acquisition of delayed-type hypersensitivity (DTH) to autologous melanoma cells in 19 patients with metastatic malignant melanoma. The patients were treated with an autologous melanoma cell vaccine, either given alone, or given 3 days after the administration of CY, 300 mg/m2 i.v. The DTH responses of CY-pretreated patients were significantly greater than those of control (vaccine only) patients. Thus, after two vaccine treatments, the median DTH responses (mm induration) were as follows: controls, 4 mm; CY pretreated, 11 mm; P = 0.034, Mann-Whitney U test, 2-tailed. Whereas seven of eight CY-pretreated patients developed DTH to autologous melanoma cells of at least 5 mm, only two of seven controls did so (P = 0.034, Fisher's exact test). Two patients had significant antitumor responses to treatment with CY plus vaccine, consisting of complete disappearance of skin metastases and a pulmonary nodule in one, and regression of s.c. and liver metastases in the other. Both patients remain free of melanoma after 42 and 33 mo, respectively.

Impairment of concanavalin A-inducible suppressor activity following administration of cyclophosphamide to patients with advanced cancer.

We have shown that cyclophosphamide (CY) can augment the development of delayed-type hypersensitivity to a primary antigen in patients with advanced cancer. In the present study, we administered CY (1000 mg/sq m) to 19 patients with advanced, metastatic cancer and monitored the compositional and functional changes in their peripheral blood mononuclear cells. Within 2 days of administration of CY, the lymphocyte count fell significantly (mean decrease = 26.0%) and remained significantly depressed through Day 14 with recovery beginning by Day 21. T- and B-lymphocytes were depleted to about the same degree at each time point. Moreover, there was no selective depletion of the Leu 2(+) (suppressor-cytotoxic) or Leu 3(+) (helper-inducer) subsets of T-lymphocytes. Proliferative responses to mitogens (phytohemagglutinin, concanavalin A, pokeweed mitogen) and to allogeneic cells fell significantly within 1 day of administration of CY and continued to be diminished on Day 2. However, these responses recovered to pretreatment levels by Day 3, and, in some cases, exceeded pretreatment levels on Day 7. Concanavalin A-inducible suppressor activity was also diminished on Day 1 (mean decrease, 23.4%) and Day 2 (mean decrease, 39.2%). However, in contrast to the proliferative responses, suppressor activity continued to be significantly impaired on Day 3 (mean decrease, 31.6%) and only partially recovered by Day 7 (mean decrease, 22.1%). Both concanavalin A-inducible suppression and proliferative responses declined again on Days 14 and 21. Thus, between 3 and 7 days after administration of CY, there appeared to be impairment of nonspecific T-cell-mediated suppressor activity of peripheral blood lymphocytes that was not merely a reflection of impaired lymphocyte function in general. This could account for the augmented delayed-type hypersensitivity responses of CY-treated patients.

Tumor-induced interleukin-10 inhibits type 1 immune responses directed at a tumor antigen as well as a non-tumor antigen present at the tumor site.

Interleukin (IL)-10 is a potent immunosuppressive cytokine that has been found to be present at the tumor site in a wide variety of human cancers, including transitional cell carcinoma of the bladder. Using a murine bladder tumor (MB49), which we show to express the male transplantation antigen (HY), we tested the hypothesis that IL-10 at the tumor site can block the generation of a tumor-specific type 1 immune response. We show that, despite its expression of HY, MB49 fails to prime for an HY-specific type 1 (IFN-gamma) response in normal female mice. Although MB49 does not constitutively produce IL-10, our data support a model whereby MB49 induces infiltrating cells to produce IL-10. This feature rendered the IL-10 knockout (KO) mouse, whose infiltrating cells are incapable of IL-10 production, a suitable model in which to study MB49 in the absence of IL-10. When injected into IL-10 KO mice, MB49 does prime for an HY-specific, type 1 immune response. Furthermore, IL-10 KO mice show prolonged survival and an increased capacity to reject tumors as compared with normal mice. We also tested the ability of tumor-induced IL-10 to inhibit immunization to a non-tumor antigen present at the tumor site. When vaccinia virus encoding beta-galactosidase (beta-gal) is injected into the tumors of normal mice, no beta-gal-specific IFN-gamma response is mounted. However, when this same viral construct is injected into the tumors of IL-10 KO mice, it produces a strong beta-gal-specific, IFN-gamma response. These studies demonstrate that tumor-induced IL-10 can block the generation of a tumor-specific type 1 immune response as well as subvert attempts to elicit a type 1 immune response to a non-tumor antigen at the tumor site.

Immunization with haptenized, autologous tumor cells induces inflammation of human melanoma metastases.

Twenty-four patients with metastatic melanoma were treated with a novel form of active immunotherapy, autologous tumor cell vaccine conjugated to the hapten, dinitrophenyl. This approach is based on the idea, well established in animal systems, that presentation of tumor antigens in the context of a strongly immunogenic hapten augments the development of immunity to those antigens. After being sensitized to dinitrophenyl, patients were given injections of dinitrophenyl-vaccine every 28 days following pretreatment with low dose cyclophosphamide. The vaccine induced a striking inflammatory response in superficial metastases in 14 of 24 patients, consisting of erythema, swelling, warmth, and tenderness over tumor masses. Immunohistochemistry and flow cytometric analysis of biopsy specimens showed marked infiltration with lymphocytes, the majority of which were CD8+, HLA-DR+ T-cells. These observations suggest that a T-cell-mediated immune response against melanoma-associated antigens was facilitated by the "helper" effect of the anti-hapten response.

Expression pattern of the neu (NGL) gene-encoded growth factor receptor protein (p185neu) in normal and transformed epithelial tissues of the digestive tract.

The neu gene (also called NGL, erbB-2, and HER-2) encodes a 185-190 kDa transmembrane glycoprotein, p185neu, which has tyrosine-specific kinase activity and is homologous to but distinct from the epidermal growth factor receptor. The normal expression of neu mRNA and protein has been demonstrated in epithelial tissues of adult animals. Also, activation of the neu oncogene has been implicated in a variety of human adenocarcinomas. In the present study, we examined the expression of the p185neu protein in normal and transformed digestive tract tissues and in a panel of digestive tract-derived cell lines. By immunohistochemistry, strong reactivity was observed in the mucosal epithelium of the stomach, small intestine, and colon of both rodents and humans. In the small intestine, there was prominent p185neu expression by mucosal epithelium of the villus, with little or no staining in the crypts. Prominent expression was observed in the liver parenchyma, the endocrine and exocrine portions of the pancreas, and in the salivary gland. Immunoreactive p185neu was also demonstrated in fetal human intestinal epithelium. Tissue sections of selected benign and malignant colonic neoplasms were also examined. Immunoreactivity was consistently greater in adenomatous polyps than in adjacent normal colonic epithelium or areas showing malignant degeneration. By radioimmunoprecipitation, there was decreased expression in cell lines derived from more anaplastic colonic tumors. The p185neu protein is expressed widely in normal and transformed epithelial tissues of the digestive tract of the adult rat and human. This finding suggests that p185neu, a putative growth factor receptor, may play a role in the regulation of normal growth and function or in the malignant transformation of these cells.

Treatment of metastatic melanoma with an autologous tumor-cell vaccine: clinical and immunologic results in 64 patients.

We treated 64 patients with metastatic melanoma using a melanoma vaccine preceded by low-dose cyclophosphamide (CY), and monitored immunologic effects and antitumor activity. On day 0, the patients were given CY 300 mg/m2 intravenously. Three days later, they were injected intradermally with vaccine consisting of 10 to 25 x 10(6) autologous, enzymatically dissociated, cryopreserved, irradiated (25 Gy) tumor cells mixed with bacillus Calmette-Guérin (BCG). This treatment sequence was repeated every 28 days. Of 40 assessable patients with measurable metastases, five had responses, four complete and one partial, with a median duration of 10 months (7 to 84+ months). In six additional patients, we observed an antitumor response that seems to be peculiar to this vaccine therapy: the regression of metastatic lesions that appeared after the immunotherapy was begun. Delayed-type hypersensitivity (DTH) to autologous, mechanically dissociated melanoma cells that had not been exposed to extraneous antigens, such as enzymes or fetal calf serum, increased significantly following immunotherapy (day 0 v day 49, P less than .001; day 0 v day 161, P less than .001; day 0 v day 217, P = .021). Antitumor responses to the vaccine were strongly associated with DTH, as indicated by three observations: (1) eight of 10 patients who exhibited tumor regression had positive DTH, (2) in postsurgical adjuvant patients, there was a highly significant linear relationship (P less than .001) between the intensity of DTH to autologous melanoma cells and the time to recurrence of tumor, and (3) nine patients who developed DTH to the autologous melanoma cells in their original vaccine developed new metastases that failed to elicit DTH or elicited a much smaller response. In three cases, we were able to excise regressing tumors for histologic examination; such tumors were characterized by an intense infiltration of lymphocytes. This demonstration that an immune response to melanoma-associated antigens can be elicited in cancer-bearing patients provides some basis for optimism about the prospects for developing active immunotherapy that has practical therapeutic value.

Autologous hapten-modified melanoma vaccine as postsurgical adjuvant treatment after resection of nodal metastases.

PURPOSE: To determine whether treatment with an autologous whole-cell vaccine modified with the hapten dinitrophenyl (DNP vaccine) is an effective postsurgical adjuvant treatment for melanoma patients with clinically evident nodal metastases. PATIENTS AND METHODS: Eligible patients had regional nodal metastases that were large enough (> or = 3 cm diameter) to prepare vaccine. Following standard lymphadenectomy, patients were treated with DNP vaccine on a monthly or weekly schedule. RESULTS: Of 62 patients with metastasis in a single lymph node bed (stage III), 36 are alive after a median follow-up time of 55 months (range, 29 to 76); the projected 5-year relapse-free and overall survival rates are 45% and 58%, respectively. Of 15 patients with metastases in two nodal sites, five are alive with a median follow-up time of 73 months. An unexpected finding was the significantly better survival of older patients; the projected 5-year survival of patients greater than 50 versus < or = 50 years was 71% and 47%, respectively (P = .011, log-rank test). The development of a positive delayed-type hypersensitivity (DTH) response to unmodified autologous melanoma cells was associated with significantly longer 5-year survival (71% v 49%; P = .031). Finally, the median survival time from date of first recurrence was significantly longer for patients whose subcutaneous recurrence exhibited an inflammatory response (> 19.4 v 5.9 months; P < .001). CONCLUSION: Postsurgical adjuvant therapy with autologous DNP-modified vaccine appears to produce survival rates that are markedly higher than have been reported with surgery alone. Moreover, this approach has some intriguing immunobiologic features that might provide insights into the human tumor-host relationship.

The spontaneous loss of contact sensitivity in the mouse does not require B cells.

In the mouse, allergic contact dermatitis to the strong contact allergen dinitrofluorobenzene is maximal 5 to 6 days after sensitization and rapidly fades in the succeeding days. It has been proposed that this loss of T-cell reactivity depends on feedback inhibition by anti-idiotypic antibody of the expression of allergic contact dermatitis. We have examined this question by studying the course of allergic contact dermatitis in mice made B-cell deficient by the chronic administration from birth of a heterologous antibody with specificity for mouse IgM. We found in these mice a spontaneous loss of allergic contact dermatitis comparable to that seen in normal intact mice. This implies that the rapid rise and fall of contact sensitivity in the mouse is not necessarily mediated by B cells (or B-cell products) and is compatible with its control, at least in part, by T-suppressor cells.

Allergic contact dermatitis in the hamster.

Allergic contact dermatitis to strong, low molecular weight contact allergens can regularly be induced in the hamster. By its clinical course, histopathology and susceptibility to intensification with complete Freund's adjuvant, this hypersensitivity appears congruent with the allergic contact dermatitis observed in other experimental animals and the allergic contact dermatitis seen in humans. Further, in the hamster, we find that pretreatment with cyclophosphamide intensifies the acquisition of allergic contact dermatitis to dinitrochlorobenzene and to oxazolone; the target of cyclophosphamide immunopotentiation has been shown in the mouse and guinea pig to be a regulator suppressor cell. In addition, we have induced in the hamster specific immune tolerance to dinitrochlorobenzene with dinitrobenzene sulfonate; in the mouse and guinea pig it has been demonstrated that the induction of specific immune tolerance to contact allergens by parenteral hapten involves the elaboration of specific suppressor cells. These findings, then, imply the existence of regulatory suppressor cells for T-cell phenomena in the hamster. This contrasts with reports that suppressor cell function in hamsters, as against other rodents, is defective as it relates to the regulation of, for instance, allogeneic reactions, antibody formation and tolerance to contact allergens.

Experimental photoallergy to systemic drugs.

We have induced photoallergy in mice to systemically administered drugs, specifically sulfanilamide and chlorpromazine. Mice were photosensitized to systemic sulfanilamide or chlorpromazine by i.p. administration of drug followed by UVB and UVA irradiation of shaved flank skin, on two consecutive days. Control mice received i.p. drug with no irradiation. In some experiments cyclophosphamide pretreatment, or intradermal Corynebacterium parvum (Propionibacterium acnes), was administered as an immunoadjuvant. All animals were photochallenged on day 5 with i.p. drug followed by UVA irradiation of one ear. Mice that had been previously immunized with drug and UV radiation developed ear swelling and erythema, evident 24 h after photochallenge, but not at 4 h. Control animals showed no reactions. In a typical experiment of photosensitization to systemic sulfanilamide, the experimental group had a mean increase in ear thickness of 6.0 X 10(-2) mm 24 h after photochallenge, while unsensitized control animals showed a mean change of -0.8 X 10(-2) mm. The histopathology of the positive challenge reaction was characteristic of a delayed type hypersensitivity. Adoptive transfer of photoallergy to systemic sulfanilamide to naive recipients was accomplished by i.v. injection of lymph node cells (5 X 10(7) harvested from actively photosensitized donors. Clinical reports have suggested that exposure to systemic medications followed by sunlight can induce an eruption having a photoallergic basis. We now report the first experimental proof of that hypothesis. The murine model should facilitate exploration of photoallergic mechanisms and, in addition, it provides the basis for a prospective test of systemic drugs for their photoallergenicity.

Experimental photoallergic contact dermatitis: a mouse model.

We have induced photoallergic contact dermatitis in mice to 3,3',4',5 tetrachlorosalicylanilide (TCSA), chlorpromazine and 6-methylcoumarin. These compounds are known to produce photoallergic contact dermatitis in humans. The photoallergic contact dermatitis reaction in the mouse is immunologically specific viz. mice photosensitized to TCSA react, by photochallenge, to that compound and not to chlorpromazine, and conversely. The reaction requires UVA at both sensitization and challenge. It appears to be T-cell mediated in that it can be passively transferred to syngeneic mice by lymph node cells from actively sensitized mice, the histology of the reactions resembles that of classic allergic contact dermatitis in mice, challenge reactions are seen at 24 but not at 4 hr, and photoallergic contact dermatitis can be induced in B-cell deficient mice. The availability of a mouse model for the study of photo-ACD will facilitate the identification of pertinent control mechanisms and may aid in the management of the disease. It is likely that a bioassay for photoallergens of humans can be based on this mouse model.

Distribution of neu (c-erbB-2) protein in human skin.

The neu (c-erbB-2) gene encodes a transmembrane protein with tyrosine kinase activity that appears to be a growth factor receptor. Antibody was generated by immunization of rabbits with a synthetic polypeptide that was based on an internal sequence at the carboxy terminus of the molecule. This antibody was used to survey the expression of neu in human skin by immunohistochemistry. Significant protein was found in the squamous cell layer of the surface epidermis, in squamous cell carcinomas, in the external root sheath of hair follicles, and in eccrine gland secretory cells; it was poorly expressed in the basal cell layer and in a basal cell carcinomas. Increased neu expression appears to be associated with the differentiation of keratinocytes.

Neutralizing anti-IL-10 antibody upregulates the induction and elicitation of contact hypersensitivity.

Various cytokines have been shown to modulate the acquisition and expression of delayed-type hypersensitivity. In a mouse model, we tested the notion that neutralization of interleukin-10 (IL-10), a cytokine that inhibits T cell-mediated reactions, would upregulate delayed-type hypersensitivity. We used two different monoclonal antibodies with specificity for murine IL-10 and used allergic contact dermatitis as a prototypical example of delayed-type hypersensitivity. When anti-IL-10 antibody was given at the time of sensitization to a contact allergen, there was a substantial increase in the induced contact hypersensitivity (CHS). In other experiments, the challenge reactions to contact allergen in routinely sensitized mice were increased when anti-IL-10 antibody was given at the time of challenge. Primary irritant reactions to croton oil were increased but only if anti-IL-10 antibody was given at the time of challenge and not when it was given a week previously. It appears that anti-IL-10 antibody can potentiate CHS reactivity by inactivating otherwise downregulating endogenous IL-10.

Coadministration of IL-12 or IL-10 expression cassettes drives immune responses toward a Th1 phenotype.

Cytokines are important regulators of the immune response. They influence immune expression, the development of immunologic memory, and regulation of antigen-specific and nonspecific immune activation as well as allergic responses. In a model system in mice, we have studied the effect of plasmids expressing interleukin (IL)-10 or IL-12 on the modulation of antigen-specific responses. Coadministration of IL-12 or IL-10 genes with DNA immunogens directed the antigen-specific immune response toward a T helper (Th1)-type immunity. In addition to the modulation of antigen-specific immune responses, we studied the induction of delayed-type hypersensitivity (DTH) to contact allergens as an in vivo model of the Th1 response. We found that IL-12 and IL-10 gene-containing plasmids, and not the bacterial plasmid alone, upregulate this response. Our cytokine gene delivery technique demonstrates an important level of control of the magnitude and direction of induced immune responses and could be advantageous in a wide variety of immunotherapeutic strategies.

Intratumoral recombinant GM-CSF-encoding virus as gene therapy in patients with cutaneous melanoma.

Seven immunocompetent, revaccinated patients with surgically incurable cutaneous melanoma underwent treatment of dermal and/or subcutaneous metastases with twice-weekly intratumoral injections of escalating doses (10(4)-2 x 10(7) plaque-forming units (PFU)/lesion; 10(4)-8 x 10(7) PFU/session) of a vaccinia/GM-CSF recombinant virus for 6 weeks. Patients with stable or responding disease were maintained on treatment until tumor resolution or progression. Systemic toxicity was infrequent, dose-related, and limited to mild flu-like symptoms that resolved within 24 hours. Local inflammation, at times with pustule formation, was consistently seen with doses of > or =10(7) PFU/lesion. Chronically treated lesions showed a dense infiltration, with CD4+ and CD8+ lymphocytes, histiocytes, and eosinophils. All seven patients developed an antivaccinia humoral immune response 14-21 days following revaccination. Despite the presence of these antivaccinia antibodies, the reporter gene was expressed, as judged by the development of anti-beta-galactosidase antibodies in all patients. Passenger cytokine gene function was evidenced by the presence of virally encoded GM-CSF mRNA at injection sites both early (weeks 1 and 5) and late (week 31) in the course of treatment. Eosinophilia at treatment sites indicated that physiologically significant levels of functional cytokine were generated. However, there were no changes in the total number of peripheral white blood cells or in the numbers or percentages of polymorphonuclear leukocytes, monocytes, or eosinophils. GM-CSF was not detected in the sera. The two patients with the largest tumor burdens failed to respond even at treatment sites. Three patients had mixed responses, with regression of treated and untreated dermal metastases and progression of disease elsewhere. One patient had a partial response, with regression of injected and uninjected regional dermal metastases. Residual melanoma was excised, rendering the patient disease free. One patient with only dermal metastases confined to the scalp achieved a complete remission. Sequential administration of escalating doses of a GM-CSF recombinant vaccinia virus is safe, effective at maintaining passenger gene function, and can induce tumor regression.

The neu (c-erbB-2) oncogene.

The neu gene was first identified in rat tumors that had been induced by the carcinogen ethyl nitrosourea. The human homolog of neu, usually designated c-erbB-2, is located on chromosome 17, q21. It specifies a transmembrane receptor-like phosphoglycoprotein that is closely related to the EGFr (c-erbB-1). The ligand for c-erbB-2 is not known. A significant proportion of adenocarcinomas (especially of the breast, colon, and pancreas) have amplification and/or overexpression of c-erbB-2. The unique qualities associated with the subset of tumors that overexpress c-erbB-2 have not yet been firmly identified.

The etiology of renal-cell carcinoma.

Experimental renal-cell carcinoma can be induced by many different chemical carcinogens; dimethyl nitrosoamine has been most studied. The disease so induced in experimental animals closely resembles the spontaneous disease in man in histopathology, course, and other characteristics. Two agents that are probably etiological of renal-cell cancer in man are tobacco and the analgesic, phenacetin; however, these materials can account for only a minority of the cases. The predominance of males in adult renal carcinoma might be explained by the more efficient metabolic activation of carcinogens by renal enzymes that are induced by male hormones. Mouse experiments support this hypothesis. Studies utilizing human kidney tissues that would test the hypothesis in man can and should be done. No obvious clues have emerged to explain the wide geographic differences in incidence of renal carcinoma. No group of industrial workers, or of others with a unique environment, has yet been described that has an especially high incidence of renal-cell carcinoma. A minority of renal carcinomas are familial. They represent a number of different diseases, one of which is associated with the von Hippel-Lindau disease. The hereditary renal-cell carcinoma of the Ecker rat, which is transmitted as an autosomal dominant, provides a useful laboratory model for hereditary carcinoma of man. Recently, two human families with renal-cell carcinoma were described in which there were unique chromosomal abnormalities associated with the disease. Such changes have been linked with oncogene activation in the instance of other tumors. Further studies of chromosomal abnormalities in renal-cell carcinoma will probably define a common pattern of chromosomal rearrangements. While estrogen readily induces renal-cell carcinoma in hamsters other species, including man, appear resistant. An excess of renal-cell carcinoma has not been reported in men on chronic estrogen therapy for prostatic carcinoma, nor has it been associated with the DES syndrome. A virus etiology for renal-cell carcinoma in man comparable to that of the Lucke tumor in frogs is unlikely on epidemiologic, ultrastructural morphologic, and other grounds. There is nothing suggesting horizontal transmission in the human disease, and a unique excess of renal-cell carcinomas in immunosuppressed patients or patients with the acquired immunodeficiency syndrome (AIDS) is not apparent. There is overwhelming evidence that renal adenomas represent early adenocarcinomas, or at least precursor lesions; certainly they are closely related to renal-cell carcinomas.(ABSTRACT TRUNCATED AT 400 WORDS)

Detection of specific genetic alterations in cancer cells.

The genetic changes found in human neoplasms suggest that hematopoietic tumors develop mainly from inappropriate expression (usually overexpression) of a growth promoting gene (oncogene). In contrast, the progression to malignancy of carcinomas occurs mainly through loss of tumor suppressor genes. Gene therapy might be used to turn off an activated oncogene, eg, by antisense treatment, whereas gene therapy to overcome tumor suppressor gene loss necessarily would focus on gene replacement in the tumor cell or pharmacologically substituting for lost gene function. On the other hand, the protein products of mutations that activate oncogenes or that inactivate tumor suppressor genes are both potential tumor antigens. Increasingly, characterization of the molecular changes that contribute to the malignant phenotype provides information impacting on tumor diagnosis and patient prognosis.