Incorporating Routine Magnetic Resonance Imaging-based Planning for the Delivery of High-dose-rate Brachytherapy for Prostate Cancer: An Evaluation of Clinical Feasibility and Dosimetric Outcomes.

Introduction To evaluate the implementation and dosimetric outcomes of magnetic resonance imaging (MRI) planning for improved target and normal tissue definition for the treatment of prostate cancer with high-dose-rate brachytherapy (HDRBT). Methods From August 2015 to October 2017, 137 unique patients with newly diagnosed localized prostate cancer underwent a total of 174 outpatient brachytherapy procedures using MRI-based treatment planning. Patients receiving brachytherapy as monotherapy underwent two separate procedures while those receiving brachytherapy as a boost after external beam radiation therapy underwent a single procedure. The target volume was defined as the prostate +/- seminal vesicles as clinically appropriate without any additional margin. Pre-treatment dose-volume histogram (DVH) goals to the target were: D90≥95%, V90≥95%, V100≥90%, V150≤30%, V200≤15%. DVH goals to organs-at-risk (OARs): urethra D.01cc ≤115%, bladder D1cc ≤75%, rectum D1cc ≤75%, neurovascular bundle D0.1cc ≤100%, penile bulb D1cc ≤100%. Procedure times were recorded at each step of the procedure, from catheter insertion to removal. Results The median target volume was 45.9 cc, the median volume receiving the prescription dose was 53.0 cc, and the median selectivity index was 0.9. The median values for target dosimetry were as follows: D90=99.9%, V90=95.7%, V100=90.1%, V150=28.1%, V200=10.5%. The median values for OAR dosimetry were: urethra D.01cc=114.3%, bladder D1cc=68.3%, rectum D1cc=51.8%, left neurovascular bundle D0.1cc=86.8%, right neurovascular bundle D0.1cc=88.5%, penile bulb D1cc=31.7%. The median time from catheter insertion to end of HDRBT delivery was four hours 14 minutes (range 2:56-9:08); total treatment package time was five hours 32 minutes (range 3:31-9:45). Conclusion Routine MRI-based treatment planning is feasible for the delivery of HDRBT for prostate cancer. We met stringent dosimetric criteria despite more objective target and normal tissue definition with MRI imaging. Treatment package time remains reasonable. We have adopted MRI as our standard imaging modality for HDRBT for prostate cancer.

GammaKnife versus VMAT radiosurgery plan quality for many brain metastases.

The purpose of this work was to compare dose distributions between two radiosurgery modalities, single-isocenter volumetric modulated arc therapy (VMAT), and GammaKnife Perfexion (GK), in the treatment of a large number (≥7) of brain metastases. Twelve patients with 103 brain metastases were analyzed. The median number of targets per patient was 8 (range: 7-14). GK plans were compared to noncoplanar VMAT plans using both 6-MV flattening filter-free (FFF) and 10-MV FFF modes. Parameters analyzed included radiation therapy oncology group conformity index (CI), 12, 6, and 3 Gy isodose volumes (V12 Gy, V6 Gy, V3 Gy), mean and maximum hippocampal dose, and maximum skin dose. There were statistically significant differences in CI (2.5 ± 1.6 vs 1.6 ± 0.8 and 1.7 ± 0.9, P < 0.001, P < 0.001), V12 Gy (2.8 ± 6.1 cc vs 3.0 ± 5.2 cc and 3.1 ± 5.4 cc, P = 0.003, P < 0.001), and V3 Gy (323.0 ± 294.8 cc vs, 880.1 ± 369.1 cc and 937.9 ±  vs 361.9 cc, P = 0.005, P = 0.001) between GK versus both 6-MV FFF and 10-MV FFF. No significant differences existed for maximum hippocampal or skin doses. In conclusion, highly optimized VMAT produced improved conformity at the expense of a higher V12 Gy and V3 Gy volume when compared with highly optimized GK.

Locoregional and Overall Recurrence After Neaodjuvant Endocrine Therapy Versus Chemotherapy in Postmenopausal Women With Estrogen Receptor+ HER2- Breast Cancer.

PURPOSE: We report clinical outcomes in patients treated with neoadjuvant endocrine therapy (NET) versus neoadjuvant cytotoxic chemotherapy (NCT) in a cohort of postmenopausal women with ER+, HER2- breast cancer. MATERIALS AND METHODS: We retrospectively reviewed 140 patients treated between May 1998 and September 2010 and collected patient, disease, and treatment characteristics, response to neoadjuvant therapy, and clinical outcome. RESULTS: The median age was 59.5 years. Stage group: stage I 2.2%, stage II 26.8%, stage III 71%, the median tumor size 6 cm (range, 1.5 to 19 cm). Fifty-seven (40.7%) received NET and 83 (59.3%) NCT. One patient (1.8%) in the NET group and 7 (8.4%) in the NCT group had a pathologic complete response (P=0.142). The median follow-up was 48.1 months. Five-year cumulative incidence of locoregional recurrence (LRR) among the entire cohort was 4.1% (95% confidence interval [CI]: 1.5, 8.9), and any recurrence 25.3% (95% CI: 17.6, 33.6). There was no difference in cumulative incidence of LRR or overall recurrence between NET and NCT. On multivariate analysis adjusting for receipt of chemotherapy, presenting stage, and positive lymph nodes, the use of adjuvant radiation therapy was associated with decreased risk of LRR (hazard ratio [HR]=0.24, P=0.035), and ypN2 status with higher risk of LRR (HR=4.91, P=0.032). When the same multivariate model was fitted for any recurrence outcome, only ypN2 status was a significant predictor of overall recurrence (HR=3.02, P=0.005). CONCLUSIONS: We have demonstrated equivalent locoregional and overall outcomes in patients receiving NET versus NCT in a cohort of postmenopausal women with locally advanced ER+HER2-tumors.

Role of Gamma Knife® Radiosurgery for the Treatment of Brain Metastases from Gynecological Cancers.

OBJECTIVE: Gamma Knife® (GK) (Elekta Instruments, Stockholm, Sweden) radiosurgery is well established for treatment of brain metastases. There are limited data on patients treated with GK from gynecological cancers. The authors sought to determine the effectiveness of the GK in patients with brain metastases from gynecological cancers. METHODS: An IRB-approved database was queried for patients with gynecologic cancers treated with GK between June 1996 and May 2016. Imaging studies were reviewed post-SRS (stereotactic radiosurgery) to evaluate local control (LC) and distant brain control (DC). Overall survival (OS), local control, and distant brain control were calculated using the Kaplan-Meier (KM) method and log-rank test.  Results: Thirty-three patients underwent SRS for 73 separate cranial lesions. The median age was -58.5 years, and 17 (52%) also had extracranial metastases. Ten (30%) patients had previously received whole brain radiotherapy (WBRT), and 11 (33%) underwent concurrent WBRT. The median tumor volume was 0.96 cm3. Median radiographic follow-up was 11 months. At the time of treatment, 39% of patients were categorized as recursive partitioning analysis (RPA) Class I, 55% as RPA Class II, and 6% as RPA Class III. The local failure rate was 8%. Five patients (15%) developed new brain lesions outside the radiation field with a median progression-free survival (PFS) of seven (range: 3-9) months. Median OS was 15 months from GK treatment. One-year OS was 72.9% from GK treatment. Primary cancer histology was a significant predictor of OS, favoring ovarian and endometrial cancer (p = 0.03). CONCLUSIONS: Gamma Knife stereotactic radiosurgery for gynecologic brain metastases leads to excellent control rates of treated lesions. Primary histology may have a significant impact on OS following GK, with improved survival seen with ovarian and cervical cancer following Gamma Knife radiosurgery (p = 0.03).

Phase I/II prospective trial of cancer-specific imaging using ultrasound spectrum analysis tissue-type imaging to guide dose-painting prostate brachytherapy.

PURPOSE: To assess the technical feasibility, toxicity, dosimetry, and preliminary efficacy of dose-painting brachytherapy guided by ultrasound spectrum analysis tissue-type imaging (TTI) in low-risk, localized prostate cancer. METHODS AND MATERIALS: Fourteen men with prostate cancer who were candidates for brachytherapy as sole treatment were prospectively enrolled. Treatment planning goal was to escalate the tumor dose to 200% with a modest de-escalation of dose to remaining prostate compared with our standard. Primary end points included technical feasibility of TTI-guided brachytherapy and equivalent or better toxicity compared with standard brachytherapy. Secondary end points included dose escalation to tumor regions and de-escalated dose to nontumor regions on the preimplant plan, negative prostate biopsy at 2 years, and freedom from biochemical failure. RESULTS: Thirteen of fourteen men successfully completed the TTI-guided brachytherapy procedure for a feasibility rate of 93%. A software malfunction resulted in switching one patient from TTI-guided to standard brachytherapy. An average of 2.7 foci per patient was demonstrated and treated with an escalated dose. Dosimetric goals on preplan were achieved. One patient expired from unrelated causes 65 days after brachytherapy. Toxicity was at least as low as standard brachytherapy. Two-year prostate biopsies were obtained from six men; five (83%) were definitively negative, one showed evidence of disease with treatment effect, and none were positive. No patients experienced biochemical recurrence after a median followup of 31.5 (24-52) months. CONCLUSIONS: We have demonstrated that TTI-guided dose-painting prostate brachytherapy is technically feasible and results in clinical outcomes that are encouraging in terms of low toxicity and successful biochemical disease control.

Concurrent radiotherapy with Carboplatin and cetuximab for the treatment of medically compromised patients with locoregionally advanced head and neck squamous cell carcinoma.

BACKGROUND: Cetuximab (Cx) + radiation therapy (RT) is well-tolerated and has improved survival in patients (pts) with locoregionally advanced head and neck squamous cell carcinomas (LA-HNSCC). However, its efficacy when compared to HD-DDP + RT has been questioned. At our institution, low-dose weekly carboplatin is added to Cx + RT for patients unsuitable for HD-DDP. METHODS: We reviewed records of 16 patients with LA-HNSCC treated with definitive Cx + carboplatin + RT at the University of Miami from 2007 to 2011. Median follow-up was 24 months (range: 1-69 months). RESULTS: Median age: 71.5 years (range: 57-90 years); 15 male, 1 female. ECOG PS 0 = 15, 1 = 1. TNM staging was: T 1 = 1, T 2 = 5, T 3 = 8, T 4 = 2; N stage: N 0 = 8, N 1 = 5, N 2a = 2, N 2b = 1. All patients received weekly carboplatin (AUC 1.5-2), Cx given conventionally and daily conventionally fractionated RT. Median total weeks of concurrent systemic therapy = 7 (range: 3-8 weeks). RT was delivered to a median total dose of 70 Gy (range 30-74 Gy). Of the 15 evaluable patients, there were: 12 CR, 2 PR, and 1 PD. There were three local in-field failures, two regional failures, and three distant failures. At last follow-up, 8/15 patients remained with NED. Three-year locoregional recurrence was 28.3% (95% CI: 7.7-53.9%). Mean percentage of weight loss was 14% (range: 6-26%). Two patients required systemic therapy dose reduction. Three patients experienced a treatment delay and three did not finish RT as planned including a patient who received only 30 Gy due to death secondary to MI during treatment. CONCLUSION: In this small retrospective series, carboplatin/Cx/RT was well-tolerated and efficacious in patients unsuitable for HD-DDP having LA-HNSCC. Acute toxicities were similar to Cx + RT, likely due to the non-overlapping toxicity profiles of the two systemic agents. We hypothesize that the addition of a well-tolerated cytotoxic chemotherapy agent may improve the therapeutic ratio of Cx + RT in patients who are poor candidates for more aggressive therapies and warrants evaluation in a prospective manner.

Novel Use of Endoscopic Clips as Fiducials for Radiotherapy in Small Bowel Lymphoma.

A 31-year-old woman was diagnosed with duodenal grade 1 follicular lymphoma. The patient underwent radiotherapy and on surveillance enteroscopy, the lymphoma was persistently identified in the duodenum and jejunum. Endoscopic clips were used as fiducials to better localize the tumor during radiotherapy. Endoscopic clips are increasingly used as tumor localization tools because of their favorable risk-benefit ratio. In our case, endoscopic clipping was necessary to properly localize the tumor after prior treatment failure, and the patient now has no evidence of disease. Larger studies are needed to demonstrate the efficacy of clips in tumor localization and improved disease-related morbidity.

Risk factors for locoregional failure in patients with inflammatory breast cancer treated with trimodality therapy.

PURPOSE: To compare patterns of local and regional failure between patients with inflammatory breast cancer (IBC) and non-IBC in patients treated with trimodality therapy. MATERIALS AND METHODS: We reviewed records of 463 patients with stage II/III breast cancer, including IBC, who completed trimodality therapy from January 1999 to December 2009. RESULTS: The median follow-up was 46.3 months (range, 4-152 months). Clinical stage was 29.4% (n = 136) II, 56.4% (n = 261) non-IBC III, 14.2% (n = 66) IBC, 30.5% (n = 141) cN0/Nx, and 69.5% (n = 322) N1-N3c. All the patients received neoadjuvant therapy and mastectomy (98%, n = 456 with axillary dissection), and all had postmastectomy radiation therapy to the chest wall with or without supraclavicular nodes (82.5%, n = 382) with or without axilla (6%, n = 28). The median chest wall dose was 60.4 Gy. Patients with IBC presented with larger tumors (P < .001) and exhibited a poorer response to neoadjuvant therapy: after surgery, fewer patients with IBC were ypN0 (P = .003) and more had ≥ 4 positive nodes (P < .001). Four-year cumulative incidence of locoregional recurrence was 5.9%, with 25 locoregional events, 9 of which had a regional component. On multivariate analysis, triple-negative disease (hazard ratio [HR] 7.75, P < .0001) and residual pathologic nodes (HR 7.10, P < .001) were associated with an increased risk of locoregional recurrence, but IBC was not. However, on multivariate analysis, the 4-year cumulative incidence of regional recurrence specifically was significantly higher in IBC (HR 9.87, P = .005). CONCLUSION: In this cohort of patients who completed trimodality therapy, the patients with IBC were more likely to have residual disease in the axilla after neoadjuvant therapy and were at greater risk of regional recurrence. Future study should focus on optimizing regional nodal management in IBC.

Predictors of locoregional outcome in patients receiving neoadjuvant therapy and postmastectomy radiation.

BACKGROUND: The objective of this study was to identify predictors of locoregional recurrence (LRR) after neoadjuvant therapy (NAT) and postmastectomy radiation (PMRT) in a cohort of patients with stage II through III breast cancer and to determine whether omission of the supraclavicular field had an impact on the risk of LRR. METHODS: The authors reviewed records from 464 patients who received NAT and PMRT from January 1999 to December 2009. RESULTS: The median patient age was 50 years (range, 25-81 years). Clinical disease stage was stage II in 29% of patients, stage III in 71%, and inflammatory in 14%. Receptor status was estrogen receptor (ER)-positive in 54% of patients, progesterone receptor (PR)-positive in 39%, human epidermal growth factor receptor 2 (HER2)-positive in 24%, and negative for all 3 receptors (triple negative) in 32%. All patients received NAT and underwent mastectomy, and 19.6% had a complete pathologic response in the breast and axilla, 17.5% received radiation to the chest wall only, and 82.5% received radiation to the chest wall and the supraclavicular field; omission of the supraclavicular field was more common in patients with lower clinical and pathologic lymph node status. The median follow-up was 50.5 months, and the 5-year cumulative incidence of LRR was 6% (95% confidence interval, 3.9%-8.6%). Predictors of LRR were clinical stage III (P = .038), higher clinical lymph node status (P = .025), higher pathologic lymph node status (P = .003), the combination of clinically and pathologically positive lymph nodes (P < .001), inflammatory presentation (P = .037), negative ER status (P = .006), negative PR status (P = .015), triple-negative status (P < .001), and pathologic tumor size >2 cm (P = .045). On univariate analysis, omission of the supraclavicular field was not associated significantly with LRR (hazard ratio, 0.89; P = .833); however, on multivariate analyses, omission of the supraclavicular field was associated significantly with LRR (hazard ratio, 3.39; P = .024). CONCLUSIONS: Presenting stage, receptor status, pathologic response to neoadjuvant therapy, and omission the supraclavicular field were identified as risk factors for LRR after neoadjuvant therapy and PMRT.

Mucosal melanomas of the head and neck: the role of postoperative radiation therapy.

Objectives. Mucosal melanomas are rarer than their cutaneous counterparts and are associated with a poorer prognosis. We report the clinical outcomes of patients with mucosal melanomas of the head and neck region generally treated with definitive surgery followed by postoperative radiation therapy (RT). Methods. We reviewed the records of 17 patients treated at the University of Miami in 1990-2007. Patients generally received conventionally fractionated RT regimens to the postoperative bed. Elective nodal RT was not routinely delivered. Eight patients received adjuvant chemotherapy or immunotherapy. Results. Median followup was 35.2 months (range 5-225). As the first site of failure: 3 patients recurred locally, 2 regionally and 2 distantly. All 3 patients who recurred locally had not received RT. Of the 5 locoregional recurrences, 4 were salvaged successfully with multimodality therapy with no evidence of disease at last followup. Overall survival was 64.7% at 2 years and 51.5% at 5 years. Conclusions. Patients with mucosal melanoma of the head and neck are best treated with surgery to achieve negative margins, followed by postoperative RT to optimize local control. Elective nodal irradiation may not be indicated in all cases, as regional failures were not predominant. Distant metastases were fewer when compared to historical data, potentially due to advancements in adjuvant therapies as well as aggressive multi-modality salvage at time of failure.

Accelerated partial breast irradiation is safe and effective using intensity-modulated radiation therapy in selected early-stage breast cancer.

PURPOSE: To report the feasibility, toxicity, cosmesis, and efficacy of using intensity-modulated radiation therapy (IMRT) with respiratory gating to deliver accelerated partial breast irradiation (APBI) in selected Stage I/II breast cancer after breast-conserving surgery. METHODS AND MATERIALS: Eligible patients with node-negative Stage I/II breast cancer were prospectively enrolled in an institutional review board approved protocol to receive APBI using IMRT after breast-conserving surgery. The target volume was treated at 3.8 Gy/fraction twice daily for 5 days, to a total dose of 38 Gy. RESULTS: Thirty-six patients were enrolled for a median follow-up time of 44.8 months. The median tumor size was 0.98 cm (range, 0.08-3 cm). The median clinical target volume (CTV) treated was 71.4 cc (range, 19-231 cc), with the mean dose to the CTV being 38.96 Gy. Acute toxicities included Grade 1 erythema in 44% of patients and Grade 2 in 6%, Grade 1 hyperpigmentation in 31% of patients and Grade 2 in 3%, and Grade 1 breast/chest wall tenderness in 14% of patients. No Grade 3/4 acute toxicities were observed. Grade 1 and 2 late toxicities as edema, fibrosis, and residual hyperpigmentation occurred in 14% and 11% of patients, respectively; Grade 3 telangiectasis was observed in 3% of patients. The overall cosmetic outcome was considered "excellent" or "good" by 94% of patients and 97% when rated by the physician, respectively. The local control rate was 97%; 1 patient died of a non-cancer-related cause. CONCLUSIONS: APBI can be safely and effectively administered using IMRT. In retrospective analysis, IMRT enabled the achievement of normal tissue dose constraints as outlined by Radiation Therapy Oncology Group 04-13/NSABP B-13 while providing excellent conformality for the CTV. Local control and cosmesis have remained excellent at current follow-up, with acceptable rates of acute/late toxicities. Our data suggest that cosmesis is dependent on target volume size. Further prospective multi-institutional trials should be performed to evaluate IMRT to deliver APBI.

A Phase I Study using low-dose fractionated whole abdominal radiotherapy as a chemopotentiator to full-dose cisplatin for optimally debulked stage III/IV carcinoma of the endometrium.

OBJECTIVE: To evaluate the feasibility of combining low-dose fractionated whole abdominal radiation (LDF-WAR) with weekly full-dose cisplatin (FD-CDDP) for patients with stage III/IV endometrial carcinoma. METHODS: Patients with optimally debulked stage III/IV carcinoma of the endometrium (without extra-abdominal disease) were eligible for the study. Postoperatively, patients received the institutional standard systemic chemotherapy and vaginal brachytherapy. Patients then underwent experimental six weekly cycles of FD-CDDP (40 mg/m², maximum 70 mg IV) followed by LDF-WAR 6-8 hours after initiation of chemotherapy. In a conservative design, 6 patients were accrued to two sequential cohorts of LDF-WAR, at 0.5 Gy/fraction [Fx] (total 3 Gy) and 0.75 Gy/Fx (total 4.5 Gy). Toxicities and laboratory studies were evaluated at each visit. RESULTS: Twelve patients were enrolled from January 2005 to June 2009 with median follow-up of 13.5 months (range: 5-27 months). Seventy-five percent of enrolled patients had uterine papillary serous histology. Eleven patients at least partially completed therapy (range: 2-6 cycles of FD-CDDP/LDF-WAR) with one additional patient opting out at the higher dose level. Combination therapy overall was well tolerated. Three patients in each cohort experienced grade 3 acute hematologic events with one recorded grade 4 toxicity in the second cohort. Of patients receiving any of the experimental treatment, five have experienced recurrences. Three of these patients were in cohort one and received 0.5 Gy/Fx LDF-WAR. CONCLUSION: Combination therapy with LDF-WAR as a novel chemopotentiator to FD-CDDP is a feasible adjuvant regimen in optimally debulked patients with stage III/IV endometrial carcinoma. Further investigation is warranted to determine treatment efficacy.

Proteomic signatures of epidermal growth factor receptor and survival signal pathways correspond to gefitinib sensitivity in head and neck cancer.

PURPOSE: Gefitinib targeting of the epidermal growth factor receptor (EGFR) has shown limited activity in clinical trials of head and neck squamous cell carcinoma (HNSCC). To investigate the underlying molecular mechanism, the proteomic signatures and responses of EGFR and downstream signals have been studied in a panel of HNSCC cell lines and tumor specimens pre- and post-gefitinib treatment. EXPERIMENTAL DESIGN: The IC(50) of gefitinib for HNSCC cell lines were determined using 3-(4,5-dmethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide proliferation assay. The effects of gefitinib on activation of EGFR and downstream signaling molecules were determined by Western blot, ELISA, and reverse-phase protein microarray (RPMA). The biomarkers involved in the signaling pathways were examined in HNSCC tumor specimens from patients in a phase I gefitinib trial. RESULTS: In vitro, gefitinib inhibited cell proliferation with differing IC(50), and suppressed activation of EGFR and downstream signaling molecules protein kinase B (AKT), extracellular signal-regulated kinase 1/2, signal transducer and activator of transcription 3 (STAT3), and nuclear factor kappaB. The drug sensitivity was statistically correlated with activation of phosphorylated AKT (p-AKT) and phosphorylated STAT3 (p-STAT3) detected by ELISA, and consistent with results measured by RPMA. In patient samples, a broad suppression of activation of EGFR and downstream signaling molecules was observed in a molecular responder patient, in contrast to a lack of inhibition or increased activation of biomarkers in different pathways in nonresponder patients. CONCLUSIONS: Gefitinib sensitivity is correlated with p-AKT and p-STAT3 activation in HNSCC cell lines and tumor specimens. p-AKT and p-STAT3 could serve as potentially useful biomarkers and drug targets for further development of novel therapeutic agents for HNSCC.

Bortezomib-induced apoptosis with limited clinical response is accompanied by inhibition of canonical but not alternative nuclear factor-{kappa}B subunits in head and neck cancer.

PURPOSE: Nuclear factor-kappaB (NF-kappaB)/REL transcription factors promote cancer cell survival and progression. The canonical (NF-kappaB1/RELA or cREL) and alternate (NF-kappaB2/RELB) pathways require the proteasome for cytoplasmic-nuclear translocation, prompting the investigation of bortezomib for cancer therapy. However, limited clinical activity of bortezomib has been observed in many epithelial malignancies, suggesting this could result from incomplete inhibition of NF-kappaB/RELs or other prosurvival signal pathways. EXPERIMENTAL DESIGN: To examine these possibilities, matched biopsies from 24 h posttreatment were obtained from accessible tumors of patients who received low-dose bortezomib (0.6 mg/m(2)) before reirradiation in a phase I trial for recurrent head and neck squamous cell carcinoma (HNSCC). Effects of bortezomib on apoptosis and proliferation by TUNEL and Ki67 staining were compared with nuclear staining for all five NF-kappaB subunits, phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), and phosphorylated signal transducers and activators of transcription 3 (STAT3) in tumor biopsies, and by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTP) and DNA binding assay for the five NF-kappaB subunits in HNSCC cell lines. RESULTS: HNSCC showed increased nuclear staining for all five NF-kappaB subunits, phosphorylated ERK1/2, and phosphorylated STAT3. Bortezomib treatment significantly enhanced apoptosis with inhibition of nuclear RELA in three of four tumors, but other NF-kappaB subunits, ERK1/2, and STAT3 were variably or not affected, and tumor progression was observed within 3 months. In HNSCC cell lines, 10(-8) mol/L bortezomib inhibited cell density while inhibiting tumor necrosis factor-alpha-induced and partially inhibiting basal activation of NF-kappaB1/RELA, but not NF-kappaB2/RELB. CONCLUSIONS: Although low-dose bortezomib inhibits activation of subunits of the canonical pathway, it does not block nuclear activation of the noncanonical NF-kappaB or other prosurvival signal pathways, which may contribute to the heterogeneous responses observed in HNSCC.

Systems biology-defined NF-kappaB regulons, interacting signal pathways and networks are implicated in the malignant phenotype of head and neck cancer cell lines differing in p53 status.

BACKGROUND: Aberrant activation of the nuclear factor kappaB (NF-kappaB) pathway has been previously implicated as a crucial signal promoting tumorigenesis. However, how NF-kappaB acts as a key regulatory node to modulate global gene expression, and contributes to the malignant heterogeneity of head and neck cancer, is not well understood. RESULTS: To address this question, we used a newly developed computational strategy, COGRIM (Clustering Of Gene Regulons using Integrated Modeling), to identify NF-kappaB regulons (a set of genes under regulation of the same transcription factor) for 1,265 genes differentially expressed by head and neck cancer cell lines differing in p53 status. There were 748 NF-kappaB targets predicted and individually annotated for RELA, NFkappaB1 or cREL regulation, and a prevalence of RELA related genes was observed in over-expressed clusters in a tumor subset. Using Ingenuity Pathway Analysis, the NF-kappaB targets were reverse-engineered into annotated signature networks and pathways, revealing relationships broadly altered in cancer lines (activated proinflammatory and down-regulated Wnt/beta-catenin and transforming growth factor-beta pathways), or specifically defective in cancer subsets (growth factors, cytokines, integrins, receptors and intermediate kinases). Representatives of predicted NF-kappaB target genes were experimentally validated through modulation by tumor necrosis factor-alpha or small interfering RNA for RELA or NFkappaB1. CONCLUSION: NF-kappaB globally regulates diverse gene programs that are organized in signal networks and pathways differing in cancer subsets with distinct p53 status. The concerted alterations in gene expression patterns reflect cross-talk among NF-kappaB and other pathways, which may provide a basis for molecular classifications and targeted therapeutics for heterogeneous subsets of head and neck or other cancers.