Faculty Bibliography

PURPOSE: Local-regional recurrence rates of 30%-50% have been reported after resection of high-risk malignant melanomas (multiple node involvement, extracapsular spread, deep invasion, recurrent disease, and/or microscopically involved margins). Recently, we have been offering elective radiation therapy, after definitive surgery, to selected patients who have high-risk malignant melanomas. We herein report our initial results. PATIENTS AND METHODS: From 1993 to 1999, 40 patients who underwent surgery for high-risk malignant melanomas (multiple involved lymph nodes [21 patients]; close or microscopically involved surgical margins [nine patients]; extracapsular extension [six patients]; previously resected, recurrent disease [three patients]; and/or primary tumors more than 4 mm thick [four patients]) received elective radiation therapy. Thirty-six patients received 3000 cGy in five fractions (600 cGy per fraction given twice weekly), and four patients received 3600 cGy in six fractions. RESULTS: At a median follow-up of 18.4 months (range, 3.8-74.1 months), the actuarial 5-year local-regional control rate was 84%. Systemic recurrence rates in these patients were similar to those reported for this subset of patients, and the actuarial overall survival rate at 5 years was 39%. Acute toxicity was limited to erythema of the skin and, in one instance, probable cellulitis, with no late sequelae. DISCUSSION: Elective radiation therapy (600 cGy per fraction for five or six fractions) effectively controlled residual subclinical disease after surgery; however, better adjuvant systemic therapies need to be designed to eliminate distant metastases and to alter survival rates

Tubular adenocarcinoma is an invasive mammary adenocarcinoma associated with an excellent prognosis and a low incidence of axillary metastases. However, identification of tubular adenocarcinoma by fine-needle aspiration (FNA) biopsy has proven difficult. One hundred five patients with documented 'pure' tubular adenocarcinoma were diagnosed at Tisch Hospital from August of 1992 to December of 1998. Twenty-one of these patients had an FNA before excision. We reviewed the smears of these cases and compared them with cases of fibroadenoma and fibrocystic change to identify criteria for diagnosis. Moderately to highly cellular smears with angular cellular clusters with sharp borders and oval cells outlining these clusters, dispersed single cells with minimal atypia, and the absence or paucity of dispersed bare oval nuclei in the background were features that suggest a diagnosis of tubular adenocarcinoma in our study. Attention to these features in combination with appropriate mammographic findings should preclude a false-negative diagnosis in the majority of cases of tubular adenocarcinoma diagnosed by aspiration biopsy. We point to the presence of the peripheral perpendicular cells in the characteristic tubular arrays as an important clue to the diagnosis of tubular adenocarcinoma

PURPOSE: Neoadjuvant chemotherapy for breast cancer creates new possibilities for the analysis of biological factors in the tumor and/or host, which may play a role in the response to treatment. In this study we analyzed whether changes in local antitumor immunity take place after neoadjuvant paclitaxel therapy and if they correlate with response to treatment. Experimental Design: Neoadjuvant chemotherapy (paclitaxel, 200 mg/m2 q2w, 4 treatments) was followed by definitive surgical management. Histological sections from the pre- and post-treatment surgical specimens of 25 patients were analyzed for the extent of lymphocytic infiltration and presence of tumor infiltrating lymphocytes (TILs). The cumulative apoptotic response in the tumor after the first dose of paclitaxel was also studied in 10 of 25 patients. RESULTS: Pretreatment lymphocytic infiltrate in the tumor was minimal in the majority of patients and showed no relationship with clinical response. In the patients without TILs before treatment, development of TILs after treatment was noted in 0/3 (0%) patients with stable disease, 3/12 (25%) patients with clinical partial response, and 4/6 (67%) patients with clinical complete response and pathological residual disease. These correlated with the tumor cell apoptotic response to the first dose of paclitaxel. CONCLUSIONS: These results suggest that development of TILs after treatment correlates with clinical response to neoadjuvant paclitaxel therapy. The possible mechanism(s) whereby neoadjuvant chemotherapy may lead to induction of antitumor T cells is discussed. Immunological processes may influence the response of breast cancer patients to neoadjuvant treatment

Benzo[a]pyrene (BP), a prototype polycyclic aromatic hydrocarbon (PAH), can be metabolically activated to the enantiomeric benzo[a]pyrene diol epoxides (BPDEs), (+)-(7R,8S,9S,10R)-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene and the (-)-(7S,8R,9R,10S) enantiomer. These can react with adenine residues in DNA, to produce the stereoisomeric 10S (+)- and 10R (-)-trans-anti-[BP]-N(6)-dA adducts. High-resolution NMR solution studies indicate that in DNA duplexes the 10R (-) adduct is intercalated on the 5'-side of the modified adenine, while the 10S (+) adduct is disordered, exhibits multiple adduct conformations, and is positioned on the 3'-side of the modified adenine. Duplexes containing the 10S (+) adduct positioned at A within codon 61 of the human N-ras sequence CAA are thermodynamically less stable and more easily excised by human DNA repair enzymes than those containing the 10R (-) adduct. However, the molecular origins of these differences are not understood and represent a fascinating opportunity for elucidating structure-function relationships. We have carried out a computational investigation to uncover the structural and thermodynamic origins of these effects in the 11-mer duplex sequence d(CGGACAAGAAG).d(CTTCTTGTCCG) by performing a 2-ns molecular dynamics simulation using NMR solution structures as the basis for the starting models. Then, we applied the MM-PBSA (molecular mechanics Poisson-Boltzmann surface area) method to compute free energy differences between the stereoisomeric adducts. The 10R (-) isomer is more stable by approximately 13 kcal/mol, of which approximately 10 kcal/mol is enthalpic, which agrees quite well with their observed differences in thermodynamic stability. The lower stability of the 10S (+) adduct is due to diminished stacking by the BP moiety in the intercalation pocket, more helix unwinding, and a diminished quality of Watson-Crick base pairing. The latter stems from conformational heterogeneity involving a syn-anti equilibrium of the glycosidic bond in the modified adenine residue. The lower stability and conformational heterogeneity of the 10S (+) adduct may play a role in its enhanced susceptibility to nucleotide excision repair.

A polyvalent melanoma vaccine prepared from shed antigens stimulates humoral and cellular immune responses and improves survival compared with historical controls. We conducted a double-blind, prospectively randomized, placebo-controlled trial to assess whether this vaccine could slow the progression of resected melanoma. Thirty-eight patients with resected melanoma metastatic to regional nodes (American Joint Committee on Cancer stage III) who had a particularly poor prognosis on the basis of the nodes being clinically positive or two or more histologically positive nodes were randomly assigned in a 2:1 ratio to treatment with 40 microg of melanoma or placebo (human albumin) vaccine, both of which were bound to alum as an adjuvant. Immunizations were given intradermally into the extremities every 3 weeks x 4, monthly x 3, every 3 months x 2, and then every 6 months for 5 years or until disease progression. Twenty-four patients were treated with the melanoma, and 14 patients were treated with the placebo vaccine. The groups were evenly balanced with respect to prognostic factors. Median length of observation was 2.5 years. There was no local or systemic toxicity. By Kaplan-Meier analysis, median time to disease progression was two and a half times longer in patients treated with melanoma vaccine compared with that in patients treated with placebo vaccine, i.e., 1.6 years (95% confidence interval, 1.0-3.0 years) compared with 0.6 year [95% confidence interval, 0.3-1.9 year(s)]. By Cox proportional hazards analysis, this difference was significant at P = 0.03. Overall survival was 40% longer in the melanoma vaccine-treated group (median overall survival of 3.8 years versus 2.7 years), but this difference was not statistically significant. In a double-blind and placebo-controlled trial, these results suggest that immunization with a melanoma vaccine may be able to slow the progression of melanoma. Although statistically significant, these results must be interpreted with caution because they are based on a small number of patients

The heterocyclic amine 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) is one of a group of heterocyclic amine carcinogens that exists in cooked meat and fish. It causes mutations in bacterial and mammalian assays and induces tumors in mammals. MeIQx is converted within cells to a reactive derivative which forms a major covalent adduct at carbon-8 of guanine in DNA. This adduct may alter the DNA conformation at critical stages of the replicative process, and cause mutations which initiate the carcinogenic process. Atomic resolution structures of the MeIQx-damaged DNA are not yet available experimentally. We have carried out an extensive molecular mechanics/energy minimization search to locate feasible structures for the major MeIQx adduct in DNA, using the sequence d(5'-C1-G2-C3-G4[IQ]-C5-G6-C7-3').d(5'-G8-C9-G10-C11-G12-C13-G14-3') with MeIQx modification at G4. We have created 1152 starting conformations which uniformly sampled each of the three flexible torsion angles that govern the MeIQx-DNA orientation at 15 degrees intervals, and minimized their energy. A mixture of conformations was generated, which were separated into families according to the position of the ring system of the carcinogenic amine: major groove, minor groove, and base-displaced-intercalated. While a generally similar mixture had been generated previously for the related carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) [Wu, X., et al. (1999) Chem. Res. Toxicol. 12, 895-905], differences were found which could be rationalized in terms of the additional methyl group in the MeIQx.

As melanoma cells are present in the circulation of many patients with this cancer, decreases in their number could provide an early indication of therapy effectiveness. To evaluate this possibility, we examined the effect of treatment with a melanoma vaccine on the number of melanoma cells present in the circulation. PCR was used to detect melanoma cells that expressed the melanoma-associated antigens MART-1, MAGE-3, tyrosinase and/or gp100 in 91 patients with melanoma. Melanoma cells that expressed one or more of these markers were present more often in advanced disease, i.e. in 80% of patients with advanced stage IV compared to in less than one-third of patients with less advanced disease. We then measured circulating melanoma cells in a subset of 43 of these patients who were treated with a polyvalent, shed antigen, melanoma vaccine. The vaccine contains multiple melanoma-associated antigens including MART-1, MAGE-3, tyrosinase and gp100. Immunizations were given intradermally q2-3 weeks x4 and then monthly x3. Prior to vaccine treatment, circulating melanoma cells were detected in 14 (32%) patients. Following 4 and 7 months of vaccine treatment, melanoma cells that expressed any of these markers were present in only nine (21%) and three (7%) of patients, respectively. Thus, vaccine therapy was associated with clearance of melanoma cells from the circulation in 78% of initially positive patients. As the number of these cells declined steadily with increasing length of therapy, it is unlikely that this was due to a random change in their number. Rather it suggests that the decline was a result of the therapy. These observations suggest that the presence of melanoma cells in the circulation is related to the extent of the melanoma, and that their disappearance may provide an early marker of the efficacy of therapy. However, the practical utility of assaying circulating tumor cells as a guide to the effectiveness of therapy or of prognosis will need to be confirmed by correlations with clinical outcome