Bacillus Calmette-Guerin in the treatment of adenocarcinoma of the kidney

A timeline of tumour-associated macrophage biology

Tumour progression is modulated by the local microenvironment. This environment is populated by many immune cells, of which macrophages are among the most abundant. Clinical correlative data and a plethora of preclinical studies in mouse models of cancers have shown that tumour-associated macrophages (TAMs) play a cancer-promoting role. Within the primary tumour, TAMs promote tumour cell invasion and intravasation and tumour stem cell viability and induce angiogenesis. At the metastatic site, metastasis-associated macrophages promote extravasation, tumour cell survival and persistent growth, as well as maintain tumour cell dormancy in some contexts. In both the primary and metastatic sites, TAMs are suppressive to the activities of cytotoxic T and natural killer cells that have the potential to eradicate tumours. Such activities suggest that TAMs will be a major target for therapeutic intervention. In this Perspective article, we chronologically explore the evolution of our understanding of TAM biology put into the context of major enabling advances in macrophage biology.

Trial watch: FDA-approved Toll-like receptor agonists for cancer therapy

Toll-like receptors (TLRs) have first been characterized for their capacity to detect conserved microbial components like lipopolysaccharide (LPS) and double-stranded RNA, resulting in the elicitation of potent (innate) immune responses against invading pathogens. More recently, TLRs have also been shown to promote the activation of the cognate immune system against cancer cells. Today, only three TLR agonists are approved by FDA for use in humans: the bacillus Calmette-Guérin (BCG), monophosphoryl lipid A (MPL) and imiquimod. BCG (an attenuated strain of Mycobacterium bovis) is mainly used as a vaccine against tuberculosis, but also for the immunotherapy of in situ bladder carcinoma. MPL (derived from the LPS of Salmonella minnesota) is included in the formulation of Cervarix®, a vaccine against human papillomavirus-16 and -18. Imiquimod (a synthetic imidazoquinoline) is routinely employed for actinic keratosis, superficial basal cell carcinoma, and external genital warts (condylomata acuminata). In this Trial Watch, we will summarize the results of recently completed clinical trials and discuss the progress of ongoing studies that have evaluated/are evaluating FDA-approved TLR agonists as off-label medications for cancer therapy.

Chorioallantoic urothelial tumor avatar. A clinical tool for phenotype-based therapy

In the muscle invasive bladder cancer (MIBC) standard of care treatment only patients presenting a major pathological tumor response are more likely to show the established modest 5% absolute survival benefit at 5 years after cisplatin-based neoadjuvant chemotherapy (NAC). To overcome the drawbacks of a blind NAC (i.e. late cystectomy with unnecessary NAC adverse events) with potential to survival improvements, preclinical models of urothelial carcinoma have arisen in this generation as a way to pre-determine drug resistance even before therapy is targeted. The implantation of tumor specimens in the chorioallantoic membrane (MCA) of the chicken embryo results in a high-efficiency graft, thus allowing large-scale studies of patient-derived “tumor avatar”. This article discusses a novel approach that exploits cancer multidrug resistance to provide personalized phenotype-based therapy utilizing the MIBC NAC dilemma.

Linking tumor glycolysis and immune evasion in cancer: Emerging concepts and therapeutic opportunities

Metabolic reprogramming and immune evasion are two hallmarks of cancer. Metabolic reprogramming is exemplified by cancer's propensity to utilize glucose at an exponential rate which in turn is linked with "aerobic glycolysis", popularly known as the "Warburg effect". Tumor glycolysis is pivotal for the efficient management of cellular bioenergetics and uninterrupted cancer growth. Mounting evidence suggests that tumor glycolysis also plays a key role in instigating immunosuppressive networks that are critical for cancer cells to escape immune surveillance ("immune evasion"). Recent data show that induction of cellular stress or metabolic dysregulation sensitize cancer cells to antitumor immune cells implying that metabolic reprogramming and immune evasion harmonize during cancer progression. However, the molecular link between these two hallmarks of cancer remains obscure. In this review the molecular intricacies of tumor glycolysis that facilitate immune evasion has been discussed in the light of recent research to explore immunotherapeutic potential of targeting cancer metabolism.

BCG-mediated bladder cancer immunotherapy: identifying determinants of treatment response using a calibrated mathematical model

Intravesical Bacillus Calmette Guérin (BCG) immunotherapy is considered the standard of care for treatment of non-muscle invasive bladder cancer; however the treatment parameters were established empirically. In order to evaluate potential optimization of clinical parameters of BCG induction therapy, we constructed and queried a new mathematical model. Specifically, we assessed the impact of (1) duration between resection and the first instillation; (2) BCG dose; (3) indwelling time; and (4) treatment interval of induction therapy – using cure rate as the primary endpoint. Based on available clinical and in vitro experimental data, we constructed and parameterized a stochastic mathematical model describing the interactions between BCG, the immune system, the bladder mucosa and tumor cells. The primary endpoint of the model was the probability of tumor extinction following BCG induction therapy in patients with high risk for tumor recurrence. We theoretically demonstrate that extending the duration between the resection and the first BCG instillation negatively influences treatment outcome. Simulations of higher BCG doses and longer indwelling times both improved the probability of tumor extinction. A remarkable finding was that an inter-instillation interval two times longer than the seven-day interval used in the current standard of care would substantially improve treatment outcome. We provide insight into relevant clinical questions using a novel mathematical model of BCG immunotherapy. Our model predicts an altered regimen that may decrease side effects of treatment while improving response to therapy.

Diphtheria toxin-epidermal growth factor fusion protein DAB389EGF for the treatment of bladder cancer

PURPOSE

The novel fusion protein, DAB(389)EGF, is composed of both the catalytic and the translocation domains of diphtheria toxin that are fused to the human EGF, providing a targeting and a toxicity component. We tested DAB(389)EGF for antitumor activity in both in vitro and in vivo urinary bladder cancer models.

EXPERIMENTAL DESIGN

Human bladder cancer lines were treated with DAB(389)EGF and assessed for growth inhibition and clonogenic suppression. Using 6- to 8-week-old female athymic nude mice implanted orthotopically with HTB9 cells, DAB(389)EGF was administered intravesically twice weekly for 2 weeks. The response of the luciferase-expressing HTB9 cells was monitored via bioluminescence as the primary endpoint.

RESULTS

Treatment response with DAB(389)EGF was specific and robust, with an IC(50) ranging from 0.5 to 15 ng/mL in eight tested bladder cancer cell lines, but greater than 50 ng/mL in the EGF receptor (EGFR)-negative H520 control cell line. Simulating short-duration intravesical therapy used clinically, a 2-hour treatment exposure of DAB(389)EGF (10 ng/mL) produced clonogenic suppression in three selected bladder cancer cell lines. In vivo, luciferase activity was suppressed in five of six mice treated with DAB(389)EGF [70 μL (1 ng/μL) per mouse], as compared with only one of six mice treated with a control diphtheria toxin (DT) fusion protein. Histologic assessment of tumor clearance correlated with the bioluminescent changes observed with DAB(389)EGF treatment. Immunocompetent mice treated with intravesical DAB(389)EGF did not show any nonspecific systemic toxicity.

CONCLUSIONS

The intravesical delivery of targeted toxin fusion proteins is a novel treatment approach for non-muscle-invasive urinary bladder cancer. With appropriate targeting, the treatments are effective and well-tolerated in vivo.

IL-23 gene therapy for mouse bladder tumour cell lines

OBJECTIVES

• To evaluate the antitumour effects of IL-23 gene transfer into mouse bladder carcinoma (MBT2) cells. • To investigate the mechanisms underlying the subsequent constitutive secrection of IL-23 by the MBT2 cells

MATERIALS AND METHODS

• An expression vector containing IL-23 gene was introduced into MBT2 cells by liposome-mediated gene transfer, and secretion of IL-23 was confirmed by ELISA. • The in vivo antitumour effect of IL-23-secreting MBT2 cells (MBT2/IL-23) was examined by injecting the cells into syngeneic C3H mice. • A tumour vaccination study using mitomycin C (MMC)-treated IL-23-secreting MBT2 cells was carried out, and the usefulness of in vivo CD25 depletion for an additional vaccine effect was also investigated. • The mechanisms underlying the antitumour effects were investigated by antibody depletion of CD8 or CD4 T cells, or natural killer cells, and cells infiltrating the tumour sites in vivo were assessed using immunohistochemistry.

RESULTS

• Stable transformants transduced with MBT2/IL-23 secreted IL-23 into the culture supernatant. • Genetically engineered IL-23-secreting MBT2 cells were rejected in syngeneic mice. • MBT2/IL-23-vaccinated mice inhibited the tumour growth of parental MBT2 cells injected at a distant site and this vaccine effect was enhanced by combination with in vivo CD25 depletion by an antibody. • The main effector cells for the direct antitumour effect of MBT2/IL-23 were CD8 T cells, which was shown by in vivo depletion and immunohistochemical study.

CONCLUSIONS

• IL-23-secreting MBT2 cells were rejected in syngeneic mice by the activation of CD8 T cells. • MMC-treated MBT2/IL-23 can have a tumour vaccine effect for parental MBT2 cells, and this effect was enhanced by combination with in vivo CD25 depletion.

The fibronectin attachment protein of bacillus Calmette-Guerin (BCG) mediates antitumor activity

PURPOSE

The receptor responsible for the attachment of bacillus Calmette-Guerin (BCG) to fibronectin, fibronectin attachment protein (FAP), has been cloned. Studies targeting FAP as an inducer of immunity in mycobacterial infections suggest that FAP is a highly immunogenic protein. In light of these findings and the need to find effective alternatives to BCG treatment for bladder cancer, we tested the ability of FAP to induce antitumor activity.

MATERIALS AND METHODS

The ability of FAP to bind to bladder tumor cells and the bladder wall was established using (125)I-FAP. For testing antitumor activity in vivo, mice were catheterized and 5 x 10(4) MB-49 bladder tumor cells were implanted orthotopically on day 0. Test groups were treated with PBS only, FAP, or BCG on day 1 and day 8. A subset of mice was preimmunized with FAP prior to treatment.

RESULTS

FAP was observed to bind to bladder tumor cells in a fibronectin-dependent manner. Attachment of FAP within the bladder followed the pattern established for BCG binding. Antitumor studies showed a significant reduction in tumor growth in FAP-treated mice that had been preimmunized with FAP. Tumor growth was not inhibited in naïve mice treated with FAP. Dose-response studies showed that FAP-induced antitumor activity is dose dependent, and experiments comparing BCG with FAP showed equivalent antitumor effects. In vitro experiments showed antigen-specific lymphocyte proliferation and a cytokine profile indicative of Th-1 polarization of the FAP-induced immune response. CD8+ T cells and natural killer cells were found to be required for the FAP-induced antitumor response.

CONCLUSIONS

FAP is an effective antitumor agent that inhibits tumor growth at a level equivalent to that observed for BCG. This protein may thus provide an alternative to BCG for treatment of superficial bladder cancer.

Enhancing the immunotherapeutic potential of mycobacteria by transfection with tumour necrosis factor-alpha

In an attempt to enhance the anti-tumour properties of mycobacteria we have developed recombinant forms of Mycobacterium smegmatis which express and secrete biologically active human tumour necrosis factor-alpha (TNF-alpha). This was achieved by transfecting M. smegmatis using shuttle plasmids incorporating the cDNA sequence for the human TNF-alpha mature peptide. In vitro experiments on a panel of human bladder tumour cell lines (EJ18, MGH-U1, RT4, RT112) indicate that our genetically modified mycobacteria are more effective than wild-type at inducing or up-regulating the expression of intracellular adhesion molecule-1 and the secretion of an array of proinflammatory cytokines [interleukin-1 (IL-1), IL-6, IL-8, granulocyte-macrophage colony-stimulating factor]. We have also demonstrated increased adhesion molecule and cytokine expression in response to mycobacteria transfected with vector containing no gene insert. However, this was not as pronounced as that observed following tumour cell stimulation by the TNF-alpha-transfected strain. In contrast, in three out of four tumour cell lines all M. smegmatis strains were found to down-regulate the secretion of the anti-inflammatory cytokine transforming growth factor-beta1. Our studies have also confirmed that M. smegmatis is a powerful inhibitor of bladder tumour cell growth and revealed that its antiproliferative potency is enhanced by transfecting with human TNF-alpha and, to a lesser extent, with vector alone. All M. smegmatis strains were effective in the activation of peripheral blood leucocyte cultures. However, no differences were observed in the ability of the TNF-alpha-transfected, mock-transfected and wild-type mycobacteria to induce tumour cell killing activity. These results suggest that the immunomodulatory effects of M. smegmatis can be enhanced by transfection with vectors which allow the secretion of human TNF-alpha, thus increasing mycobacterial immunotherapeutic potential.

Application of the interferon minipellet to human renal cell carcinoma in nude mice

BACKGROUND

The interferon (IFN) minipellet is a sustained-release formulation of human lymphoblastoid IFN, with atelocollagen used as the carrier material. We evaluated the antitumor effect of the IFN minipellet on an established human renal cell carcinoma cell line (KU-2) transplanted in nude mice.

METHODS

The treatment was started when tumor nodules had grown to 6 to 8 mm in diameter. The IFN minipellet, or an aqueous solution of IFN, was given by subcutaneous injection, or peritumor injection, on days 1 and 10. Antitumor effects were evaluated according to tumor weights calculated as (long diameter) x (short diameter)2/2 in 7 groups consisting of 6 mice each.

RESULTS

IFN levels remained detectable in both tumor tissue and serum up to 10 days after peritumor injection of the IFN minipellet. Administered by the peritumor route, the IFN minipellet inhibited growth of the tumor significantly as compared with tumor growth in the untreated mice. The IFN minipellet showed greater inhibition of tumor growth by peritumor injection compared to subcutaneous injection. The aqueous solution of IFN was not effective either by subcutaneous or by peritumoral injection.

CONCLUSION

Results indicate that the IFN minipellet is useful in the treatment of renal cell carcinoma.

Immunotherapy of renal cell cancer

Immunotherapy of metastatic renal adenocarcinoma (RCC) is currently an alternative to cytotoxic chemotherapy. Bacillus Calmette-Guérin has been associated with a 22% response rate in small series, but no large-scale clinical trials have been completed. Transfer factor, in combination with other immunotherapeutic and chemotherapeutic compounds, has a reported 13% incidence of response. Tumor vaccines have caused clinical response in only 5% of patients while monoclonal antibodies have produced partial remission in one of nine patients. Immune RNA has been associated with a 14% overall incidence of response. Tumor necrosis factor has not as yet been studied in any large-scale clinical investigations but preliminary studies are not promising. Leukocyte-derived and recombinant interferons alone have produced responses in 10-20% of patients with tolerable toxicity. Combinations of interferons or with cytotoxic chemotherapy have produced slightly improved responses with short duration and substantial toxicity. Adoptive immunotherapy using Interleukin-2 alone, or with IL-2 plus lymphocyte-activated killer cells, or tumor infiltrating lymphocytes or interferons have produced clinical responses in 10-30% of patients treated. Combinations of specific forms of immune therapy may hold promise for better rates of clinical response in the future.

Differential sensitivity of renal cell carcinoma xenografts towards therapy with interferon-alpha, interferon-gamma, tumor necrosis factor and their combinations

Whereas cytokine therapy has proven efficacy in the treatment of metastatic renal cell carcinoma (RCC), many questions regarding the use of these drugs remain unanswered. In the present study we evaluated the antiproliferative effects of human recombinant alpha-interferon (IFN), gamma-interferon and tumor necrosis factor-alpha (TNF) on eight human RCC xenografts. In particular, the importance of the administration route, dosage and tumor load was investigated. Response to the cytokines differed widely amongst the different tumors. Of three tested routes of administration (i.v., i.p. and s.c. peritumoral), only the s.c. peritumoral route was effective against tumor growth. After 6 weeks of therapy consisting of 150 or 1,500 units IFN/g given s.c. peritumorally three times a week or 30,000 units TNF/g given five times a week, alpha-IFN treatment resulted in 2%-100% growth inhibition; gamma-IFN, in 7%-80%; and TNF, in 35%-75% as compared with the untreated control. Growth of five of eight tumor lines could be inhibited completely by combinations of IFN and TNF, whereby the tumor dimensions at the beginning of therapy were decisive for the results. In some cases IFNs had optimal doses; however, the antitumor effects of TNF were always dose-dependent. Our studies indicate that the doses at which the optimal direct effects of cytokines are measured are critically dependent on the tumor treated. Although direct effects are only one part of the mode of action of cytokines, our results indicate that dosage of cytokines may need individualisation.

Surgical treatment of brain metastases from renal cell carcinoma

Between January 1976 and December 1986, 22 patients with renal cell carcinoma underwent surgical resection of brain metastases at Memorial Sloan-Kettering Cancer Center. Ten of the patients had metastases limited to the brain and 12 also had extracranial metastases. Twenty patients received external radiotherapy. Five had craniotomy after failing radiation therapy and 15 had adjuvant radiotherapy. Two patients died within thirty days following craniotomy; the median survival of the remaining 20 patients was 20.9 +/- 6.8 months calculated according to a Weibull survival model. Variables examined in relation to survival included absence or presence of extracranial metastases at time of craniotomy, time interval between nephrectomy and diagnosis of cerebral metastases, neurologic status prior to craniotomy, location of the brain tumor, and patient age. None of the variables was significant at the 10 percent level by the Weibull analysis. However, three favorable prognostic factors, namely metachronous brain metastasis more than one year after nephrectomy, minimal or no neurologic deficit at time of craniotomy, and infratentorial lesions show a trend toward improved survival with p less than 0.20. The data suggest that surgical resection of a single and occasionally multiple brain metastases is warranted in selected patients with renal cell carcinoma.

Metastatic renal cell cancer and radical nephrectomy: identification of prognostic factors and patient survival

Between January 1, 1970 and December 31, 1980 (followup 2 years or more) 158 patients with histologically proved metastatic renal cell cancer and no prior therapy were seen. Statistical analyses identified variables that significantly influenced survival, including grade of the primary lesion (p equals 0.002), weight loss of more than 10 per cent (p less than 0.0001) and multiple versus single metastases (p equals 0.0001). Cell type, soft tissue versus bone metastasis, age, sex, site and size of primary lesion, and delay in the diagnosis did not influence survival significantly. Adjuvant nephrectomy markedly influenced survival only in patients with solitary metastasis, low grade primary tumor and weight loss of less than 10 per cent (p equals 0.06). Based on this analysis a score system was constructed to help predict survival and the impact of new forms of therapy in the future.

Prophylaxis and therapy of an experimental bladder cancer with biological response modifiers

We have previously reported that the intraperitoneal injection of viable bacillus Calmette-Guerin (BCG) reduces the incidence of tumor takes and the rate of tumor growth and also increases tumor regression rate and survival in C3H/HeN mice challenged with the syngeneic MBT-2 bladder cancer. We have now investigated the immunoprophylactic effect of BCG and other biological response modifiers. Groups of 12 to 15 female C3H/HeN mice were challenged with 5 X 10(5) MBT-2 viable cells and treated with BCG, poly I:C, tilorone, levamisole or a combination of these agents. Appropriate controls were included in each experiment. In this study we confirmed previous findings that BCG alone is effective in prophylaxis and can also decrease the rate of tumor growth in those animals not protected against tumor takes. Both i.p. levamisole and oral tilorone lacked activity against the MBT-2 tumor. A single i.p. injection of poly I:C was also ineffective although its repeated administration reduced the rate of tumor growth and induced a significant number of tumor regressions. Combined therapy of BCG with either levamisole or tilorone offered no therapeutic advantage over BCG alone. Heat-inactivated BCG also failed to induce anti-tumor activity in C3H/HeN mice challenged with MBT-2 cells. These results indicate that live BCG remains the most active immunoprophylactic and immunotherapeutic agent against the MBT-2 murine bladder cancer. Furthermore, the anti-tumor effect of viable BCG is not potentiated further by the addition of other immune modulating agents.

Characterization of a renal cell carcinoma cell line suitable as a target for immunological studies in vitro and in the nu/nu mouse

A continuous human renal carcinoma cell line designated RPMI-SE was established from a patient with a poorly to moderately differentiated renal cell carcinoma. The cells are anchorage dependent, have a well defined globular shape with pseudopod-like structures, a doubling time in vitro of 24 hr. and are able to grow subcutaneously in female ICR Swiss nu/nu mice. RPMI-SE cells obtained from tissue culture and the nude mouse had the chromosome number of near-tetraploidy. Common morphologic rearrangements were present in both the cell line and nu/nu mouse tumor. RPMI-SE was evaluated as a target cell line in an in vitro Indium-111 release assay. Three patterns of cytotoxicity were observed at an effector to target cell ratio of 100:1. The highest degree of cytotoxicity (75 per cent) was obtained with autologous lymphocytes. An intermediate level of cytotoxicity (50 per cent) was obtained with allogeneic lymphocytes. The lowest level of cytotoxicity (27 per cent) was obtained with normal lymphocytes and was comparable to the level of cytotoxicity observed with the NK sensitive K562 target cell line. Morphologic data and chromosomal analysis indicate that the RPMI-SE cell line has maintained characteristics of the original tumor. This cell line will be useful for immunological studies as a target cell line in vitro as well as in vivo in the nude mouse.

Renal cell carcinoma--angioinfarction

In our experience the mortality rate in 46 patients who underwent angioinfarction for renal cell carcinoma was 4 per cent. Fever, ileus and leukocytosis were noted in 86 to 90 per cent of our patients. The use of absolute ethanol as a medium for renal infarction was associated with a significant incidence of damage to other organs. A 30 per cent decrease in tumor volume following angioinfarction using absorbable gelatin sponge and Gianturco coils was noted in 75 per cent of the patients. There was no evidence of metastatic tumor reduction and we could not document any significant decrease in operative time or blood loss. It would appear that there is some increased survival rate in patients with metastasis who are given adjuvant immune ribonucleic acid therapy. However, the numbers in our series are not significant to draw any definite conclusion. It is apparent that patients treated with infarction, delayed nephrectomy and medroxyprogesterone acetate did not have any significant survival over those treated with palliative nephrectomy or chemotherapy. The macrophage maturation assay may be useful during clinical followup.

A critical review of immunotherapy of disseminated renal adenocarcinoma

Sixty patients with renal adenocarcinoma have been treated with five different immunotherapy trials consisting of 1) Transfer Factor (TF), 2) TF and Bacillus Calmette-Guerin (BCG), 3) TF, BCG, Chloroethyl-cyclohexy-nitrosurea (CCNU) and megestrol acetate (Megase), 4) BCG, CCNU, and Megase, or 5) BCG. Using strict response criteria for measurable disease, objective responses were seen in 14-22% of cases. While this nonspecific immunotherapy of renal adenocarcinoma has been associated with documented regression of metastases, response rates are similar to that obtained with hormonal therapy alone. Objective responses support the concept of further trials in this disease with more sophisticated immunotherapy.

Cytoreductive surgery and systemic bacillus Calmette-Guerin therapy in metastatic renal cancer: a phase II trial

A phase II trial has been conducted to determine the effect upon survival of cytoreductive surgery (nephrectomy) and adjuvant active immunotherapy (bacillus Calmette-Guerin) in patients with stage IV renal cancer. A total of 20 patients underwent removal of the primary tumor and received bacillus Calmette-Guerin therapy (adjuvant group). The results were compared to those obtained in 20 historical controls treated with conventional methods (hormones, chemotherapy and radiotherapy with or without nephrectomy) and 16 concurrent controls. All patients in the historical control group were dead within 4 years after the diagnosis of metastases. Seven patients (35 per cent) in the adjuvant group were alive 2 to 5 years after documentation of metastatic disease and onset of therapy. The ratio of observed to expected deaths in the adjuvant group was 0.59 compared to 1.6 in the historical controls. This superior survival was statistically significant (p less than 0.01). A difference in survival between the adjuvant group and concurrent controls also was present but was not statistically significant (0.10 less than p less than 0.20). Other factors suspected to influence survival were investigated. We found that in addition to bacillus Calmette-Guerin therapy a prolonged interval free of disease and better performance status had a better prognosis. Location of metastases, nephrectomy, age and sex are of no significant prognostic value. Definitive answers on the therapeutic value of bacillus Calmette-Guerin and the influence on survival of various biological factors can only be provided by large, controlled, randomized and stratified (phase III) trials.

Renal cell carcinoma: long-term survival and late recurrence

In a series of 506 patients with renal cell carcinoma survival was analyzed in terms of pathologic stage, histologic grade, and a combination of stage and grade. Data reveal that stage, grade and the combination are important prognostic indicators. Invasion of the renal pelvis is not an important factor in staging the disease. Women had a better survival rate than men. The prognosis for patients with dark cell tumors was no worse than that for patients with clear cell tumors when correlated with the more important factors of tumor stage and grade. Renal vein involvement alone, excluding concomitant capsular or nodal involvement, had an adverse effect on survival. Of the patients who survived 10 years from the date of nephrectomy 11 per cent had late recurrence.

Quantitation of a whole blood assay for human natural killer cell activity

A method is described for the measurement of human natural killer cell activity using heparinized whole blood in a 51chromium release assay. Fractionation-reconstitution experiments showed that the cytotoxic activity was abolished by removal of the Fc receptor bearing lymphocytes, but not by the elimination of monocytes and granulocytes. Autologous or pooled plasma was not found to possess inherent cytolytic activity. By analogy to an enzyme kinetic reaction, the results were expressed as kinetic lytic units (KLU) which were defined as the maximum number of target cells that could be lysed per unit time per milliliter of whole blood. The buffy coat cytotoxicity (BCC) assay is quick, easy to perform, and suitable for screening and monitoring of natural cytotoxicity. Since this methodology preserves the actual concentration of natural killer cells, it may represent a truer reflection of in vivo events.

Spontaneous regression of metastases of renal cancer: A report of two cases including the first recorded regression following irradiation of a dominant metastasis and review of the world literature

Two cases of spontaneous regression of lung metastases are presented. One is the first report of regression of metastases after irradiation of a dominant metastasis. The world literature is reviewed, and 67 documented cases have been found including the two now reported. Attention is drawn to the use of immunotherapy in the treatment of advanced renal cancer.

Active specific immunotherapy of stage IV renal carcinoma with aggregated tumor antigen adjuvant

Active-specific immunotherapy of human malignancy with a vaccine consisting of admixtures of modified tumor antigens and an adjuvant such as tuberculin has not been fully explored, despite preliminary reports of clinical success and conceptual support from animal studies. Three years ago, we designed a prospective study using aggregated soluble tumor antigens admixed with tuberculin or phytohemagglutinin as an adjuvant (TAA) in order to treat patients with Stage IV renal carcinoma. Autologous tumor vaccines were used initially in 24 patients with operatively accessible tumor, although most patients eventually were switched to allogeneic preparations. Scarifications with Bacillus-Calmette Guerin were used in order to ensure maximum reactivity to tuberculin and patients received no other therapy while in the study. Two patients achieved complete remission and 2, partial remission. The overall survival rate for the 30 patients entered is equivalent to reported survival rates for patients with extensive disease treated with aggressive surgery with or without chemotherapy. We believe these results offer strong preliminary evidence of efficacy of this particular type of therapy in an advanced human malignancy.

Aggressive versus conservative management of stage IV renal cell carcinoma

Improved modalities to treat metastatic renal cell carcinoma will require an aggressive surgical and chemotherapeutic approach. Nephrectomy with hormonal and non-hormonal chemotherapy does improve median survival and 3-year survival significantly. The use of xenogeneic specific immune ribonucleic acid and Bacillus Calmette-Guerin offers promising immunotherapeutic modalities that may be combined with surgical and chemotherapeutic regimens. Early diagnosis of metastatic disease is important to evaluate properly the results of various modalities of treatment and possibly to improve the efficiency of these modalities. The management of solitary metastatic nodules should involve aggressive resection of the primary and metastatic nodule. Adjuvant hormonal and non-hormonal chemotherapy should be considered in all stages of the disease.

Nephrectomy for renal cell carcinoma with metastases

The percentage of patients with renal cell carcinoma who also have identifiable metastases when first seen is increasing. In the past metastases were considered justification for excluding nephrectomy in the management of the patient. However, numerous opportunities for therapy which are abetted by removal of the primary tumor are presented. It is concluded, depending on several variables, that the advantages of nephrectomy usually justify the procedure.

Intracavitary Bacillus Calmette-Guerin in the treatment of superficial bladder tumors

Patients with recurrent superficial bladder tumors have been treated by vesical and intradermal administration of Bacillus Calmette-Guerin. The pattern of recurrence in 9 patients has been altered favorably. Although the findings are still preliminary they appear to hold promise of a new therapeutic approach to the treatment of a group of neoplasms for which effective therapy is still lacking.

Immune reactivity in renal cancer: a sequential study

We evaluated 18 patients with adenocarcinoma of the kidney immunologically in a linear fashion. Delayed cutaneous hypersensitivity was significantly altered in patients with metastatic disease. In vitro studies have shown a progressive decline in the absolute number of circulating lymphocytes and the T cell subpopulations that parallels the advance of the maligant process. Evaluation of lymphocyte function by the response to mitogens appears to be of little significance in a sequential study.