Andy Sherrod

FCGR2A and FCGR3A Polymorphisms Associated With Clinical Outcome of Epidermal Growth Factor Receptor–Expressing Metastatic Colorectal Cancer Patients Treated With Single-Agent Cetuximab

PURPOSE Cetuximab, a chimeric immunoglobulin G 1 (IgG1) anti-epidermal growth factor receptor (EGFR) monoclonal antibody (mAb), has shown efficacy in 10% of patients with metastatic colorectal cancer (CRC). Recent studies demonstrate antibody-dependent cell-mediated cytotoxicity (ADCC) is one of the modes of action for rituximab and trastuzumab. Fragment c (Fc) portion of IgG1 mAb has shown to induce ADCC. Fragment c gamma receptors (FcgammaR) play an important role in initiating ADCC. Studies have shown that two IgG FcgammaR polymorphisms (FCGR2A-H131R and FCGR3A-V158F) independently predict response to rituximab in patients with follicular lymphoma. We tested the hypothesis of whether these two polymorphisms are associated with clinical outcome in metastatic CRC patients treated with single-agent cetuximab. PATIENTS AND METHODS Thirty-nine metastatic CRC patients were enrolled onto the ImClone0144 trial. Using an allele-specific polymerase chain reaction (PCR) -based method, gene polymorphisms of FCGA2A-H131R and FCGA3A-V158F were assessed from genomic DNA extracted from peripheral blood samples. RESULTS FCGR2A-H131R and FCGR3A-V158F polymorphisms were independently associated with progression-free survival (PFS; P = .037 and .055, respectively; log-rank test). Combined analysis of these two polymorphisms showed that patients with the favorable genotypes (FCGR2A, any histidine allele, and FCGR3A, any phenylalanine allele) showed a median PFS of 3.7 months (95% CI, 2.4 to 4.4 months), whereas patients with any two unfavorable genotypes (FCGR2A arginine/arginine or valine/valine) had a PFS of 1.1 months (95% CI, 1.0 to 1.4 months; P = .004; log-rank test). CONCLUSION Our preliminary data suggest that these two polymorphisms may be useful molecular markers to predict clinical outcome in metastatic CRC patients treated with cetuximab and that they may indicate a role of ADCC of cetuximab.

Molecular Determinants of Cetuximab Efficacy

PURPOSE To investigate whether mRNA expression levels of cyclin D1 (CCND1), cyclooxygenase 2 (Cox-2), epidermal growth factor receptor (EGFR), interleukin 8 (IL-8), and vascular endothelial growth factor (VEGF), all members of the EGFR signaling pathway, are associated with clinical outcome in patients with EGFR-expressing metastatic colorectal cancer (CRC) treated with cetuximab. PATIENTS AND METHODS Thirty-nine patients with metastatic CRC, refractory to both irinotecan and oxaliplatin, were enrolled on IMCL-0144 and treated with single-agent cetuximab. The intratumoral mRNA levels of CCND1, Cox-2, EGFR, IL-8, and VEGF were assessed from paraffin-embedded tissue samples using laser-capture microdissection and quantitative real-time polymerase chain reaction. RESULTS There were 21 women and 18 men with a median age of 64 years (range, 35 to 83 years). Higher gene expression levels of VEGF were associated with resistance to cetuximab (P = .038; Kruskal-Wallis test). The combination of low gene expression levels of Cox-2, EGFR, and IL-8 was significantly associated with overall survival (13.5 v 2.3 months; P = .028; log-rank test). Both findings were independent of skin toxicity that was itself significantly correlated to survival. Patients with a lower mRNA amount of EGFR had a longer overall survival compared with patients that had a higher mRNA amount (7.3 v 2.2 months; P = .09; log-rank test). Patients with lower expression of Cox-2 had a significantly higher rate of grade 2 to 3 skin reactions under cetuximab treatment. CONCLUSION This pilot study suggests that gene expression levels of Cox-2, EGFR, IL-8, and VEGF in patients with metastatic CRC may be useful markers of clinical outcome in single-agent cetuximab treatment.

Liposome-Encapsulated Doxorubicin in Combination With Standard Agents (cyclophosphamide, vincristine, prednisone) in Patients With Newly Diagnosed AIDS-Related Non-Hodgkin's Lymphoma: Results of Therapy and Correlates of Response

PURPOSE To evaluate the safety and efficacy of liposomal doxorubicin (Myocet; Medeus Pharma Ltd, Herts,UK) when substituted for doxorubicin in the CHOP regimen (cyclophosphamide, doxorubicin, vincristine, prednisone) in patients with newly diagnosed AIDS-related non-Hodgkins lymphoma (AIDS-NHL). Secondary objectives were to assess the impact of HIV viral control on response and survival, and to correlate MDR-1 expression with outcome. PATIENTS AND METHODS Liposomal doxorubicin at doses of 40, 50, 60, and 80 mg/m(2) was given with fixed doses of cyclophosphamide, vincristine, and prednisone every 21 days. All patients received concurrent highly active antiretroviral therapy. NHL tissues were evaluated for multidrug resistance (MDR-1) expression. RESULTS Twenty-four patients were accrued. 67% had high or high-intermediate International Prognostic Index scores; the median CD4 lymphocyte count was 112/mm(3) (range, 19/mm(3) to 791/mm(3)). No dose-limiting toxicities were observed at any level, with myelosuppression being the most frequent toxicity. Overall response rate was 88%, with 75% complete responses (CRs), and 13% partial responses. The median duration of CR was 15.6+ months (range, 1.7 to 43.5+ months). Effective HIV viral control during chemotherapy was associated with significantly improved survival (P =.027), but CRs were attained independent of HIV viral control. MDR-1 expression did not correlate with response, suggesting that the liposomal doxorubicin may evade this resistance mechanism. CONCLUSION Liposomal doxorubicin in combination with cyclophosphamide, vincristine, and prednisone is active in AIDS-NHL, with complete remissions achieved in 75% independent of HIV viral control or tissue MDR-1 expression. HIV viral control is associated with a significant improvement in survival. Additional studies are warranted.

Intermediate filament expression in astrocytic neoplasms.

Immunohistochemical analysis of 30 paraffin-embedded astrocytic neoplasms was performed to correlate the expression of intermediate filament proteins with histologic subtype. Each tumor was studied with monoclonal antibodies to keratin, vimentin, desmin, 200-kd neurofilament protein, and glial fibrillary acidic protein (GFAP). Immunoreactivity with the anti-keratin monoclonal antibodies AE1 and AE3 was demonstrated in 24 cases (80%) including 4 of 6 (66%) well-differentiated astrocytomas (WDAs), 10 of 12 (83%) anaplastic astrocytomas (ANAs), and 10 of 12 (83%) glioblastomas multiforme (GBMs). These cases were further studied with the monoclonal antikeratin antibodies 34βE12 and 34βH11. Of the 24 AE1/AE3-positive cases, 14 (58%) reacted with 34βE12. None of the cases was reactive with 34βH11. Vimentin expression was demonstrated in 24 cases (80%), including 2 of 6 (33%) WDAs, 11 of 12 (92%) ANAs, and 11 of 12 (92%) GBMs. Coexpression of keratin and vimentin was observed in 20 cases (67%), including 2 of 6 WDAs, 9 of 12 (75%) ANAs, and 9 of 12 (75%) GBMs. Immunoreactivity with GFAP antibody was present in all 30 (100%) cases, but none of the tumors was reactive with antibodies to desmin or 200-kd neurofilament protein. These findings demonstrate that expression of both keratin and vimentin intermediate filaments is common in astrocytic neoplasms regardless of histologic grade.

The Effects of Extracorporeal Shock Wave Lithotripsy on Renal Growth, Function and Arterial Blood Pressure in an Animal Model

The long-term effects of extracorporeal shock wave lithotripsy (ESWL*) on children treated for renal calculi are unclear. To study the long-term bio-effects of this mode of treatment on the immature animal we evaluated 30 New Zealand white rabbits at 7 weeks of age for weight, serum blood urea nitrogen and creatinine, and arterial blood pressure after which they underwent left nephrectomy. Each group of 5 rabbits received ESWL of varying levels (500 to 3,000 shock waves) to the remaining right kidney using the Northgate SD3 lithotriptor (spark gap mediated). One control group received no shock waves. At maturity (16 weeks) the aforementioned parameters were measured again, and the kidneys and any grossly abnormal adjacent organs were examined. We found no significant change in total animal growth, renal growth, renal function or perirenal organs in the post-ESWL groups versus the control group. All post-ESWL groups had an increase in mean arterial blood pressure versus the control group with 3 of 6 groups showing significant increases (p less than 0.05). Histological renal changes, seen at all energy levels of ESWL delivered, included interstitial fibrosis, tubular atrophy, glomeruli destruction, capsular thickening, perivascular fibrosis and mild arteriole wall thickening. Changes were proportional to the number of shocks received. We conclude that ESWL delivered to immature animals does not significantly affect renal growth and function but it can cause significant permanent histological renal changes even at low doses and may result in an increase in adult mean arterial blood pressure.

Molecular determinants of irinotecan efficacy

Molecular markers predicting the efficacy of CPT‐11 based chemotherapies in patients with colorectal cancer (CRC) are unknown. Therefore, we investigated whether mRNA levels of drug targets (Topoisomerase I, TS), enzymes involved in 5‐FU metabolism (DPD), in angiogenesis (EGFR, IL‐8, VEGF) and in DNA‐repair/drug detoxification (ERCC1, GST‐P1) are associated with the clinical outcome of patients with CRC treated with first‐line CPT‐11 based chemotherapy. Thirty three patients with metastatic CRC were included in the study. Intratumoral gene expression levels were assessed from paraffin‐embedded tissue samples, using laser capture microdissection and quantitative Real‐Time PCR. Complete response was observed in 1 patient, partial response in 12 patients, stable disease in 13 patients and progressive disease in 6 patients. Response was inevaluable for 1 patient. Patients with complete response or partial response were classified as responders, while patients with stable disease or progressive disease were classified as nonresponders. High intratumoral mRNA levels of EGFR, ERCC1 and GSPT‐P1 were each significantly associated with response to CPT‐11 based chemotherapy. Recursive partitioning analysis showed that mRNA levels of EGFR and ERCC1 are primarily responsible for delineating responders from nonresponders. Also, the combination of high intratumoral gene expression levels of both EGFR and ERCC1 was significantly associated with progression‐free survival. The mRNA levels of EGFR had a significant correlation with expression levels of ERCC1, GST‐P1 and VEGF. This small retrospective study suggests that gene expression levels of EGFR, ERCC1 and GST‐P1 may be useful in predicting the clinical outcome of patients with metastatic CRC treated with first‐line CPT‐11 based chemotherapy.

Multidrug resistance (MDR-1) expression in AIDS-related lymphomas.

P-glycoprotein is a product of the multidrug resistance (MDR-1) gene. In non-Hodgkins lymphoma, less than 20% of untreated de novo lymphomas express MDR-1 compared with approximately 50% after failure of chemotherapy. We wished to study the expression of MDR-1 in AIDS-related non-Hodgkins lymphoma (AIDS-NHL). Tissue biopsies from 50 patients with newly diagnosed AIDS-NHL were studied by immunohistochemical analysis using C494, a monoclonal antibody specific for the MDR-1 isoform of P-gp. MDR-1 expression was correlated with patient demographics, lymphoma characteristics, response to chemotherapy, and survival. Forty-six males and four females with a median age of 38 years (range 26-63) were studied. A prior AIDS-defining opportunistic infection was reported in 35 patients (70%). The median CD4+ lymphocyte count was 69/mm(3) (range 0-920). Thirty-two patients (63%) had received prior anti-HIV therapy, including a protease inhibitor in five (10%). Pathologic types consisted of diffuse large cell in 13 (26%), immunoblastic in 13 (26%), small non-cleaved in 22 (44%), and high grade not otherwise specified in two (4%). The majority of patients (76%) had stage III/IV disease. Pre-treatment lymphoma tissues from 33 patients (66%) stained positively for MDR-1. MDR-1 positive patients had a significantly lower complete remission rate compared to MDR-1 negative patients (33 versus 65%, P=0.042). Duration of complete response was significantly longer in MDR-1 negative patients compared with MDR-1 positive patients (not reached versus 9.9 months, P=0.003). Strategies to overcome MDR-1 expression may be important for initial treatment in patients with AIDS-NHL.

Impaired Dihydrotestosterone Catabolism in Human Prostate Cancer: Critical Role of AKR1C2 as a Pre-Receptor Regulator of Androgen Receptor Signaling

We previously reported the selective loss of AKR1C2 and AKR1C1 in prostate cancers compared with their expression in paired benign tissues. We now report that dihydrotestosterone (DHT) levels are significantly greater in prostate cancer tumors compared with their paired benign tissues. Decreased catabolism seems to account for the increased DHT levels as expression of AKR1C2 and SRD5A2 was reduced in these tumors compared with their paired benign tissues. After 4 h of incubation with benign tissue samples, (3)H-DHT was predominantly catabolized to the 5alpha-androstane-3alpha,17beta-diol metabolite. Reduced capacity to metabolize DHT was observed in tumor samples from four of five freshly isolated pairs of tissue samples, which paralleled loss of AKR1C2 and AKR1C1 expression. LAPC-4 cells transiently transfected with AKR1C1 and AKR1C2, but not AKR1C3, were able to significantly inhibit a dose-dependent, DHT-stimulated proliferation, which was associated with a significant reduction in the concentration of DHT remaining in the media. R1881-stimulated proliferation was equivalent in all transfected cells, showing that metabolism of DHT was responsible for the inhibition of proliferation. PC-3 cells overexpressing AKR1C2 and, to a lesser extent, AKR1C1 were able to significantly inhibit DHT-dependent androgen receptor reporter activity, which was abrogated by increasing DHT levels. We speculate that selective loss of AKR1C2 in prostate cancer promotes clonal expansion of tumor cells by enhancement of androgen-dependent cellular proliferation by reducing DHT metabolism.

Histological Analysis of the Kidney Tumor-Parenchyma Interface

PURPOSE During enucleative partial nephrectomy excision is performed adjacent to the tumor edge. To better determine the oncologic propriety of enucleative partial nephrectomy we histologically examined the tumor-parenchyma interface. MATERIALS AND METHODS Archived hematoxylin and eosin stained slides of 124 nephrectomy specimens were rereviewed. We evaluated representative sections of tumor abutting the renal parenchyma and overlying pseudocapsule/perirenal fat were selected at 4 mm(2) sectors apportioned 1, 2, 3 and 4 mm, respectively, from the tumor edge. RESULTS Median tumor size was 3.5 cm. Of the tumors 111 were malignant (90%) and 119 (96%) had a pseudocapsule with a median thickness of 0.6 mm. Of malignant and benign tumors 82% and 31%, respectively, had an intrarenal pseudocapsule (p < 0.001). Pseudocapsule invasion was noted in 45% of cancers and 15% of benign tumors (p < 0.04). Of pT1a cancers 36% showed intrarenal pseudocapsule invasion. No patient had positive surgical margins. Intrarenal pseudocapsule invasion correlated with clear cell renal cell carcinoma histology but not with cancer size, grade, necrosis or margin width. Inflammation, nephrosclerosis, glomerulosclerosis and arteriosclerosis decreased with increasing distance from the tumor edge. At 1 mm changes were moderate to severe in 38%, 32%, 20% and 17% of tumors while at 5 mm changes were mild in 2.5%, 0.8%, 0.8% and 4%, respectively (p <0.001). Mean arteriolar diameter decreased with tumor proximity (p < 0.0001). CONCLUSIONS Most renal cancers have an intrarenal pseudocapsule. Partial nephrectomy excision adjacent to the tumor edge appears to be histologically safe. Because 18% of cancers lacked a discernible intrarenal pseudocapsule and 25% of pT1a cancers showed intrarenal pseudocapsule invasion, extreme care is needed to avoid positive margins during enucleative partial nephrectomy.

Double-Blind Phase III Randomized Trial of the Antiprogestin Agent Mifepristone in the Treatment of Unresectable Meningioma: SWOG S9005.

PURPOSE Progesterone receptors are expressed in approximately 70% of meningiomas. Mifepristone is an oral antiprogestational agent reported to have modest activity in a phase II study. This multicenter, prospective, randomized, placebo-controlled phase III trial conducted by SWOG was planned to define the role of mifepristone in the treatment of unresectable meningioma. PATIENTS AND METHODS Eligible patients were randomly assigned to receive either mifepristone or placebo for 2 years unless disease progressed. Patients who were stable or responding to protocol therapy after 2 years had the option to continue with the same blinded therapy. Serial follow-up allowed assessment of efficacy and toxicity. Time to treatment failure and overall survival were ascertained for all randomly assigned patients. On progression, patients receiving placebo could cross over and receive active drug. RESULTS Among 164 eligible patients, 80 were randomly assigned to mifepristone and 84 to placebo. Twenty-four patients (30%) were able to complete 2 years of mifepristone without disease progression, adverse effects, or other reasons for discontinuation. Twenty-eight patients (33%) in the placebo arm completed the 2-year study. There was no statistical difference between the arms in terms of failure-free or overall survival. CONCLUSION Long-term administration of mifepristone was well tolerated but had no impact on patients with unresectable meningioma.