Target-specific requirements for RNA interference can arise through restricted RNA amplification despite the lack of specialized pathways.

Since double-stranded RNA (dsRNA) is effective for silencing a wide variety of genes, all genes are typically considered equivalent targets for such RNA interference (RNAi). Yet, loss of some regulators of RNAi in the nematode C. elegans can selectively impair the silencing of some genes. Here we show that such selective requirements can be explained by an intersecting network of regulators acting on genes with differences in their RNA metabolism. In this network, the Maelstrom domain-containing protein RDE-10, the intrinsically disordered protein MUT-16, and the Argonaute protein NRDE-3 work together so that any two are required for silencing one somatic gene, but each is singly required for silencing another somatic gene, where only the requirement for NRDE-3 can be overcome by enhanced dsRNA processing. Quantitative models and their exploratory simulations led us to find that (1) changing cis-regulatory elements of the target gene can reduce the dependence on NRDE-3, (2) animals can recover from silencing in non-dividing cells and (3) cleavage and tailing of mRNAs with UG dinucleotides, which makes them templates for amplifying small RNAs, is enriched within 'pUG zones' matching the dsRNA. Similar crosstalk between pathways and restricted amplification could result in apparently selective silencing by endogenous RNAs.

Reduced-dose radiotherapy for human papillomavirus-associated squamous-cell carcinoma of the oropharynx: a single-arm, phase 2 study.

BACKGROUND: Head and neck cancers positive for human papillomavirus (HPV) are exquisitely radiosensitive. We investigated whether chemoradiotherapy with reduced-dose radiation would maintain survival outcomes while improving tolerability for patients with HPV-positive oropharyngeal carcinoma. METHODS: We did a single-arm, phase 2 trial at two academic hospitals in the USA, enrolling patients with newly diagnosed, biopsy-proven stage III or IV squamous-cell carcinoma of the oropharynx, positive for HPV by p16 testing, and with Zubrod performance status scores of 0 or 1. Patients received two cycles of induction chemotherapy with 175 mg/m2 paclitaxel and carboplatin (target area under the curve of 6) given 21 days apart, followed by intensity-modulated radiotherapy with daily image guidance plus 30 mg/m2 paclitaxel per week concomitantly. Complete or partial responders to induction chemotherapy received 54 Gy in 27 fractions, and those with less than partial or no responses received 60 Gy in 30 fractions. The primary endpoint was progression-free survival at 2 years, assessed in all eligible patients who completed protocol treatment. This study is registered with ClinicalTrials.gov, numbers NCT02048020 and NCT01716195. FINDINGS: Between Oct 4, 2012, and March 3, 2015, 45 patients were enrolled with a median age of 60 years (IQR 54-67). One patient did not receive treatment and 44 were included in the analysis. 24 (55%) patients with complete or partial responses to induction chemotherapy received 54 Gy radiation, and 20 (45%) with less than partial responses received 60 Gy. Median follow-up was 30 months (IQR 26-37). Three (7%) patients had locoregional recurrence and one (2%) had distant metastasis; 2-year progression-free survival was 92% (95% CI 77-97). 26 (39%) of 44 patients had grade 3 adverse events, but no grade 4 events were reported. The most common grade 3 events during induction chemotherapy were leucopenia (17 [39%]) and neutropenia (five [11%]), and during chemoradiotherapy were dysphagia (four [9%]) and mucositis (four [9%]). One (2%) of 44 patients was dependent on a gastrostomy tube at 3 months and none was dependent 6 months after treatment. INTERPRETATION: Chemoradiotherapy with radiation doses reduced by 15-20% was associated with high progression-free survival and an improved toxicity profile compared with historical regimens using standard doses. Radiotherapy de-escalation has the potential to improve the therapeutic ratio and long-term function for these patients. FUNDING: University of California.

TELEHEALTH ALLOWS FOR CLINICAL TRIAL PARTICIPATION AND MULTIMODALITY THERAPY IN A RURAL PATIENT WITH STAGE 4 NON-SMALL CELL LUNG CANCER.

Oligometastatic non-small cell lung cancer (NSCLC) has a poor prognosis for rural patients with traditional therapies. Implementation of multi-modality systemic therapy in conjunction with surgical resection can dramatically improve overall survival, leading to clinical complete remission. The currently accepted indications for resection in oligometastatic NSCLC include brain and adrenal metastases. Rural populations are known to have disparities in care of complex malignancies and the use of telehealth has been shown to improve outcomes. We present a case of a rural patient with stage IV NSCLC, who was able to participate in two clinical trials, undergo trimodality therapy, and remain disease-free for 18 months, whose care was facilitated via telehealth video conferencing with a tertiary care center.

Comparative morbidity of axillary lymph node dissection and the sentinel lymph node technique: implications for patients with breast cancer.

OBJECTIVE: To assess our long-term complications from complete axillary lymph node dissection (AXLND) in patients with breast cancer. SUMMARY BACKGROUND DATA: Complete AXLND as part of the surgical therapy for breast cancer has come under increased scrutiny due the use of the sentinel lymph node (SLN) biopsy technique to assess the status of the axillary nodes. As the enthusiasm for the SLN technique has increased, our impression has been that the perceived complication rate from AXLND has increased dramatically while the negative aspects of the SLN technique have been underemphasized. METHODS: Female patients seen in routine follow-up over a 1-year period were eligible for our retrospective study of the long-term complications from AXLND if they were a minimum of 1 year out from all primary therapy; ie, surgery, radiation, and/or chemotherapy. All patients had previously undergone either a modified radical mastectomy (MRM) or a segmental mastectomy with axillary dissection and postoperative radiation (SegAx/XRT). All patients had a Level I-III dissection. Objective measurements, including upper and lower arm circumferences and body mass index (BMI), were obtained, and a subjective evaluation from the patients was conducted. RESULTS: Ninety-four patients were eligible for our study; 44 had undergone MRM, and 50 had undergone SegAx/XRT. The average number of nodes removed was 25.6 (standard deviation, 8). Thirty-three percent of the patients had positive nodal disease, 95% of the patients had an upper arm circumference within 2 cm of the unaffected side, and 93.3% had a lower arm circumference within 2 cm of the unaffected side. Subjectively, 90.4% of the patients had either no or minimal arm swelling, and 96.8% of the patients had "good" or "excellent" overall arm function. The most common long-term symptom was numbness involving the upper, inner aspect of the affected arm (25.5%). CONCLUSIONS: Our data indicate that a complete AXLND can be performed with minimal long-term morbidity. The lower the morbidity of AXLND, the less acceptable are the unique complications of the SLN technique.