Current treatment of metastatic renal cell carcinoma with xenogeneic immune ribonucleic acid

Construction of a triple modified p53 containing DNA vaccine to enhance processing and presentation of the p53 antigen

More effective and less toxic treatments are urgently needed in the treatment of patients with cancer. The tumour suppressor protein p53 is a tumour-associated antigen that could serve that purpose when applied in an immunologic approval to cancer. It is mutated in approximately 50% of the tumours resulting in p53 overexpression, which can serve as target for therapy. To improve the immunisation results in patients with p53 overexpression tumours we constructed a DNA vaccine that could lead to improved processing and presentation of p53 peptides in the MHC-class I. We constructed a triple modified p53 fusion protein containing DNA vaccine by (1) addition of a xeno-antigen (mouse or rat p53 fragment), (2) potentiation of intra-cytoplasmatic accumulation of p53 by deleting the nuclear signalling part, (3) improving the processing to peptides of p53 by addition of ubiquitin. In-vitro experiments confirmed correct construction of the DNA vaccine. Preliminary testing in normal and HLA-A2 mice of this triple modified p53 containing DNA construct meant for human application showed a trend towards a superior immunogenicity.

Medical treatment of advanced renal cell carcinoma: present options and future directions

The treatment of patients with metastatic renal cell carcinoma (MRCC) continues to be disappointing. A large number of hormones, chemotherapeutic agents and combinations have been tested with poor and non-reproducible results. Among the immunological treatments investigated in MRCC, the best results have been claimed with interferons (IFNs) and interleukin-2 (IL-2) and, although no randomized studies have shown higher activity than cytotoxic drugs, hormones or even no treatment, many oncologists feel it justified to consider these biologic agents the treatment of choice for this disease. Of patients treated with alpha-IFN, 15-20% achieve an objective remission and 3-5% achieve a long-lasting complete response. No substantial increase of the therapeutic activity of alpha-IFN was produced by combination with chemotherapeutic agents and gamma-IFN or tumour necrosis factor. High doses of IL-2 with or without lymphokine-activated killer cells led to successful results in about 20-30% of patients with 5-10% complete responses. More recently, less toxic regimens with lower doses of IL-2 alone or combined with alpha-IFN produce similar response rates. Many studies have clarified the importance of prognostic factors in patient selection for response and survival during treatments with IFNs and IL-2. Good performance status, a long interval from diagnosis to treatment, and only one site of disease seem to be the most important predictors for survival. Both IFNs and IL-2 appear to possess encouraging antitumour activity in patients with favourable prognostic factors, but further studies are needed to identify the treatment of choice, the optimal dose regimen and route of administration in this subgroup of patients. Patients with poor prognosis should be encouraged to enter controlled studies aimed to evaluate investigational drugs and new therapeutic methods.

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.

Nuclear shape analysis for assessment of prognosis in renal cell carcinoma

Clinically localized renal cell carcinoma is cured by radical nephrectomy in 47% [stage T3a (II)] to 65% [stage T1, T2 (I)] of the patients. Local recurrence and metastatic disease probably result from undetectable microscopic metastases present at operation. Chemotherapy and immunotherapy may improve cure rates if administered adjuvantly. The outcome of individual patients who share surgical stage cannot be predicted reliably by tumor histology, pathological and/or nuclear deoxyribonucleic acid analysis. Two groups of 10 patients with clinically localized renal cell carcinoma were similar by sex distribution (5 men and 5 women), surgical stage (stages T1 in 1, T2 in 6 and T3a in 3 patients) and age (54.3 +/- 15.2 standard deviation versus 55.8 +/- 8.7 years). Group 1 had no recurrences with a minimum followup of 5 years and a mean followup of 10 years. Group 2 died of metastatic renal cell carcinoma after a mean of 5 years. All neoplastic areas of each paraffin-embedded operative specimen were randomly sampled and the nuclear perimeter of 150 cancerous cells was digitized. There were 25 shape descriptors calculated for each nucleus. All shape descriptors for each patient were described by 19 statistical tests. Nuclear perimeter and area as well as mean nuclear roundness factor failed to separate the 2 groups. Range median quartiles of ellipticities by Fourier analysis, coefficients of variation of chain code minimums and relative means of largest 10 convexity values produced greatest separation (Mann-Whitney-Wilcoxon test p less than 0.001, and variance normalized difference 3.21, 3.29 and 2.83, respectively). These descriptors normalized and summed provided near perfect separation (Mann-Whitney-Wilcoxon test p less than 0.001 and variance normalized difference 3.59). We developed a quantitative nuclear morphometric analysis system that permitted the correct assignment of outcome in 19 of 20 patients. Accurate prediction of prognosis in patients with clinically localized renal cell carcinoma by nuclear shape analysis may allow for selection of patients for adjuvant therapy who have clinically undetectable metastatic disease.

Biologic response modifiers in genitourinary neoplasia

With the exception of testis cancer, the variety of genitourinary cancers have not been found to be consistently responsive to chemotherapeutic agents or regimens for other than anecdotal short duration. This has generated keen interest in the possibility that biologic response modifiers might either directly or through manipulation of immune response mechanisms successfully prevent tumor progression in these systems. In recent years, those substances that have attracted the greatest attention have included interferon (and, more recently, recombinant gamma interferon), bacillus Calmette-Guerin (BCG), tumor necrosis factor, prostaglandin synthetase inhibitors, and interleukin-2. Results with each of these agents in the variety of genitourinary cancers have been both promising and disappointing. A number of mechanisms have been suggested to underlie the actions of each of these substances, and the successful or unsuccessful recruitment of these mechanisms, in the context of the particular intrinsic behavior of the cancers being treated, have been suggested as reasons for the treatment results that have been seen. Therapeutic efficacy has been described in the treatment of renal cell cancer by both systemic interferon and interleukin-2. Successful treatments have been reported in approximately 20% of patients treated with each substance, but generally, these results have been of short duration. Topical BCG has been used with great success to treat superficial transitional cell bladder cancer. In these instances, the generation of tumor necrosis factor has been suggested as possibly accounting for the 70% success rate both in therapy and prophylaxis that has been seen. Leukocyte-derived interferon and, more recently, recombinant gamma interferon, were found in initial trials to generate a 20% response rate in renal cell carcinoma patients. Enthusiasm for these agents, however, has been tempered more recently both by a failure to reproduce these results with any substantial duration as well as by the significant side effects that have been seen. Clearly, these agents continue to be intriguing both because of their intellectual appeal through the mechanisms by which they may be effective, as well as by the absence of any definitive therapy for the cancers they are being used to treat. An understanding of the complex host/tumor cell interaction that may ultimately determine therapeutic efficacy for each of these agents is undoubtedly critical if the role of these substances in the treatment of genitourinary cancer is to be successfully implemented, either alone or in combination with other treatment modalities.