Challenges and advances in the medical treatment of granulomatous amebic encephalitis.

Granulomatous amebic encephalitis, caused by the free-living amebae Balamuthia mandrillaris or Acanthamoeba species, is a rare and deadly infectious syndrome with a current mortality rate of >90%. Much work remains to define the optimal treatment for these infections. Here, we provide a comprehensive overview of the supporting evidence behind antimicrobials currently recommended by the Centers for Disease Control and Prevention (CDC) with updated statistics on survival rates and medication usage from the CDC Free-Living Ameba Database. We also discuss promising treatments, especially the emerging therapeutic agent nitroxoline, and provide recommendations for the next steps in this area.

Engineering TALE-linked deaminases to facilitate precision adenine base editing in mitochondrial DNA.

DddA-derived cytosine base editors (DdCBEs) and transcription activator-like effector (TALE)-linked deaminases (TALEDs) catalyze targeted base editing of mitochondrial DNA (mtDNA) in eukaryotic cells, a method useful for modeling of mitochondrial genetic disorders and developing novel therapeutic modalities. Here, we report that A-to-G-editing TALEDs but not C-to-T-editing DdCBEs induce tens of thousands of transcriptome-wide off-target edits in human cells. To avoid these unwanted RNA edits, we engineered the substrate-binding site in TadA8e, the deoxy-adenine deaminase in TALEDs, and created TALED variants with fine-tuned deaminase activity. Our engineered TALED variants not only reduced RNA off-target edits by >99% but also minimized off-target mtDNA mutations and bystander edits at a target site. Unlike wild-type versions, our TALED variants were not cytotoxic and did not cause developmental arrest of mouse embryos. As a result, we obtained mice with pathogenic mtDNA mutations, associated with Leigh syndrome, which showed reduced heart rates.

clifford B.4.1 , an allele of CG1603 , causes tissue overgrowth in the Drosophila melanogaster eye.

Mutant B.4.1 , generated via EMS mutagenesis in Drosophila melanogaster , was studied by undergraduate students participating in the Fly-CURE. After inducing genetically mosaic tissue in the adult eye, B.4.1 mutant tissue displays a robust increase in cell division and a rough appearance. Complementation mapping and sequence analysis identified a nonsense mutation in the gene CG1603 , which we named clifford ( cliff ) due to observed increases in red-pigmented mutant tissue compared to controls. cliff encodes a zinc finger-containing protein implicated in transcriptional control. RNAi knockdown of cliff similarly results in rough eyes, confirming a role for Cliff in eye development.

Optimal selection of resampling methods for imbalanced data with high complexity.

Class imbalance is a major problem in classification, wherein the decision boundary is easily biased toward the majority class. A data-level solution (resampling) is one possible solution to this problem. However, several studies have shown that resampling methods can deteriorate the classification performance. This is because of the overgeneralization problem, which occurs when samples produced by the oversampling technique that should be represented in the minority class domain are introduced into the majority-class domain. This study shows that the overgeneralization problem is aggravated in complex data settings and introduces two alternate approaches to mitigate it. The first approach involves incorporating a filtering method into oversampling. The second approach is to apply undersampling. The main objective of this study is to provide guidance on selecting optimal resampling methods in imbalanced and complex datasets to improve classification performance. Simulation studies and real data analyses were performed to compare the resampling results in various scenarios with different complexities, imbalances, and sample sizes. In the case of noncomplex datasets, undersampling was found to be optimal. However, in the case of complex datasets, applying a filtering method to delete misallocated examples was optimal. In conclusion, this study can aid researchers in selecting the optimal method for resampling complex datasets.

Prime editing with genuine Cas9 nickases minimizes unwanted indels.

Unlike CRISPR-Cas9 nucleases, which yield DNA double-strand breaks (DSBs), Cas9 nickases (nCas9s), which are created by replacing key catalytic amino-acid residues in one of the two nuclease domains of S. pyogenesis Cas9 (SpCas9), produce nicks or single-strand breaks. Two SpCas9 variants, namely, nCas9 (D10A) and nCas9 (H840A), which cleave target (guide RNA-pairing) and non-target DNA strands, respectively, are widely used for various purposes, including paired nicking, homology-directed repair, base editing, and prime editing. In an effort to define the off-target nicks caused by these nickases, we perform Digenome-seq, a method based on whole genome sequencing of genomic DNA treated with a nuclease or nickase of interest, and find that nCas9 (H840A) but not nCas9 (D10A) can cleave both strands, producing unwanted DSBs, albeit less efficiently than wild-type Cas9. To inactivate the HNH nuclease domain further, we incorporate additional mutations into nCas9 (H840A). Double-mutant nCas9 (H840A + N863A) does not exhibit the DSB-inducing behavior in vitro and, either alone or in fusion with the M-MLV reverse transcriptase (prime editor, PE2 or PE3), induces a lower frequency of unwanted indels, compared to nCas9 (H840A), caused by error-prone repair of DSBs. When incorporated into prime editor and used with engineered pegRNAs (ePE3), we find that the nCas9 variant (H840A + N854A) dramatically increases the frequency of correct edits, but not unwanted indels, yielding the highest purity of editing outcomes compared to nCas9 (H840A).

Successful Treatment of Balamuthia mandrillaris Granulomatous Amebic Encephalitis with Nitroxoline.

A patient in California, USA, with rare and usually fatal Balamuthia mandrillaris granulomatous amebic encephalitis survived after receiving treatment with a regimen that included the repurposed drug nitroxoline. Nitroxoline, which is a quinolone typically used to treat urinary tract infections, was identified in a screen for drugs with amebicidal activity against Balamuthia.

Implementation of Transgender/Gender Nonbinary Care in a Family Medicine Teaching Practice.

PURPOSE: Numerous studies have shown that transgender or gender nonbinary (TGNB) individuals encounter significantly more health care barriers, including overall lack of access to gender-affirming care providers. This study describes 2 assessments of transgender care services at a large family medicine teaching practice. METHODS: Staff and providers were invited to attend an optional, practice-wide, hourlong free training session on gender-affirming care offered on 3 different dates in 2019. A structured protocol was used to collect observational data from which key takeaways from the training sessions were developed. Separately, a retrospective chart review of patients with a gender dysphoria diagnosis was completed. Charts were reviewed for adherence to regional and international organization recommendations for comprehensive transgender care. RESULTS: Three main takeaways from the training sessions included lack of knowledge or familiarity with gender terminology and expression, fear of offending patients, and employee hesitation to change behaviors when interacting with patients. On chart review, the most common interventions identified were need to schedule a follow-up visit (61.5%), need for health maintenance screenings (osteoporosis screening, 50%; Papanicolaou smear, 56.3%; mammogram, 66.7%), need for mental health screening (41.5%), need for laboratory monitoring of testosterone therapy (20%), and corrected gender markers/names listed in the appropriate place in the patient chart (16.9%). CONCLUSIONS: This study highlighted hesitation to provide and lack of familiarity with transgender care among practice staff. Although some aspects of comprehensive transgender care are well implemented, maintaining follow-up, completing health maintenance and mental health screenings, and appropriate laboratory monitoring are areas for improvement.

Effectiveness of Mobile Apps in Promoting Healthy Behavior Changes and Preventing Obesity in Children: Systematic Review.

BACKGROUND: Mobile apps have been increasingly incorporated into healthy behavior promotion interventions targeting childhood obesity. However, their effectiveness remains unclear. OBJECTIVE: This paper aims to conduct a systematic review examining the effectiveness of mobile apps aimed at preventing childhood obesity by promoting health behavior changes in diet, physical activity, or sedentary behavior in children aged 8 to 12 years. METHODS: MEDLINE, Embase, PsycINFO, CINAHL, and ERIC were systematically searched for peer-reviewed primary studies from January 2008 to July 2021, which included children aged 8 to 12 years; involved mobile app use; and targeted at least one obesity-related factor, including diet, physical activity, or sedentary behavior. Data extraction and risk of bias assessments were conducted by 2 authors. RESULTS: Of the 13 studies identified, most used a quasi-experimental design (n=8, 62%). Significant improvements in physical activity (4/8, 50% studies), dietary outcomes (5/6, 83% studies), and BMI (2/6, 33% studies) were reported. All 6 multicomponent interventions and 57% (4/7) of standalone interventions reported significant outcomes in ≥1 behavioral change outcome measured (anthropometric, physical activity, dietary, and screen time outcomes). Gamification, behavioral monitoring, and goal setting were common features of the mobile apps used in these studies. CONCLUSIONS: Apps for health behavior promotion interventions have the potential to increase the adoption of healthy behaviors among children; however, their effectiveness in improving anthropometric measures remains unclear. Further investigation of studies that use more rigorous study designs, as well as mobile apps as a standalone intervention, is needed.

Dialysis adequacy predictions using a machine learning method.

Dialysis adequacy is an important survival indicator in patients with chronic hemodialysis. However, there are inconveniences and disadvantages to measuring dialysis adequacy by blood samples. This study used machine learning models to predict dialysis adequacy in chronic hemodialysis patients using repeatedly measured data during hemodialysis. This study included 1333 hemodialysis sessions corresponding to the monthly examination dates of 61 patients. Patient demographics and clinical parameters were continuously measured from the hemodialysis machine; 240 measurements were collected from each hemodialysis session. Machine learning models (random forest and extreme gradient boosting [XGBoost]) and deep learning models (convolutional neural network and gated recurrent unit) were compared with multivariable linear regression models. The mean absolute percentage error (MAPE), root mean square error (RMSE), and Spearman's rank correlation coefficient (Corr) for each model using fivefold cross-validation were calculated as performance measurements. The XGBoost model had the best performance among all methods (MAPE = 2.500; RMSE = 2.906; Corr = 0.873). The deep learning models with convolutional neural network (MAPE = 2.835; RMSE = 3.125; Corr = 0.833) and gated recurrent unit (MAPE = 2.974; RMSE = 3.230; Corr = 0.824) had similar performances. The linear regression models had the lowest performance (MAPE = 3.284; RMSE = 3.586; Corr = 0.770) compared with other models. Machine learning methods can accurately infer hemodialysis adequacy using continuously measured data from hemodialysis machines.

Chloroplast and mitochondrial DNA editing in plants.

Plant organelles including mitochondria and chloroplasts contain their own genomes, which encode many genes essential for respiration and photosynthesis, respectively. Gene editing in plant organelles, an unmet need for plant genetics and biotechnology, has been hampered by the lack of appropriate tools for targeting DNA in these organelles. In this study, we developed a Golden Gate cloning system1, composed of 16 expression plasmids (8 for the delivery of the resulting protein to mitochondria and the other 8 for delivery to chloroplasts) and 424 transcription activator-like effector subarray plasmids, to assemble DddA-derived cytosine base editor (DdCBE)2 plasmids and used the resulting DdCBEs to efficiently promote point mutagenesis in mitochondria and chloroplasts. Our DdCBEs induced base editing in lettuce or rapeseed calli at frequencies of up to 25% (mitochondria) and 38% (chloroplasts). We also showed DNA-free base editing in chloroplasts by delivering DdCBE mRNA to lettuce protoplasts to avoid off-target mutations caused by DdCBE-encoding plasmids. Furthermore, we generated lettuce calli and plantlets with edit frequencies of up to 99%, which were resistant to streptomycin or spectinomycin, by introducing a point mutation in the chloroplast 16S rRNA gene.

Mitochondrial DNA editing in mice with DddA-TALE fusion deaminases.

DddA-derived cytosine base editors (DdCBEs), composed of the split interbacterial toxin DddAtox, transcription activator-like effector (TALE), and uracil glycosylase inhibitor (UGI), enable targeted C-to-T base conversions in mitochondrial DNA (mtDNA). Here, we demonstrate highly efficient mtDNA editing in mouse embryos using custom-designed DdCBEs. We target the mitochondrial gene, MT-ND5 (ND5), which encodes a subunit of NADH dehydrogenase that catalyzes NADH dehydration and electron transfer to ubiquinone, to obtain several mtDNA mutations, including m.G12918A associated with human mitochondrial diseases and m.C12336T that incorporates a premature stop codon, creating mitochondrial disease models in mice and demonstrating a potential for the treatment of mitochondrial disorders.

Preoperative MRI and LDH in women undergoing intra-abdominal surgery for fibroids: Effect on surgical route.

INTRODUCTION: Our institution implemented a preoperative protocol to identify high-risk cases for which power morcellation should be avoided. MATERIAL AND METHODS: In this retrospective cohort study, an institutional protocol requiring preoperative Magnetic Resonance Imaging with diffusion-weighted imaging and serum Lactate Dehydrogenase levels was implemented. Chart review was performed including all women who underwent intra-abdominal surgery for symptomatic fibroids from 4/23/2013 to 4/23/2015. RESULTS: A total of 1,085 women were included, 479 before and 606 after implementation of the Magnetic Resonance Imaging / Lactate Dehydrogenase protocol. The pre-protocol group had more post-menopausal women (4% vs. 2%, p = 0.022) and women using tamoxifen (2% vs. 0%, p = 0.022) than those in the post-protocol group, but baseline patient characteristics were otherwise similar between groups. Incidence of malignant pathological diagnoses did not change significantly over the time period in relation to protocol implementation. The rate of open surgery for both hysterectomy and myomectomy remained the same in the year preceding and the year following initiation of the protocol (open hysterectomy rate was 19% vs. 16% in pre- and post-protocol groups, respectively, P = 0.463, and open myomectomy rate was 10% vs. 9% rates in pre- and post-protocol groups, respectively, P = 0.776). There was a significant decrease in the use of power morcellation (66% in pre- and 50% in post-protocol cohorts, p<0.001) and an increased use of containment bags (1% in pre- and 19% in post-protocol cohort). When analyzing the subset of women who had abnormal Magnetic Resonance Imaging / and Lactate Dehydrogenase results, abnormal Magnetic Resonance Imaging results alone resulted in higher rates of open approach (65% for abnormal vs. 35% for normal). Similarly, a combination of abnormal Magnetic Resonance Imaging and Lactate Dehydrogenase tests resulted in higher rates of open approach (70% for abnormal and 17% for normal). Abnormal Lactate Dehydrogenase results alone did not influence route. CONCLUSIONS: Rates of MIS procedures were decreased for women with abnormal preoperative Magnetic Resonance Imaging results. False positive results appear to be one of the main drivers for the use of an open surgical route.

Off-the-Shelf, Immune-Compatible Human Embryonic Stem Cells Generated Via CRISPR-Mediated Genome Editing.

Human embryonic stem cells (hESCs) hold promise in regenerative medicine but allogeneic immune rejections caused by highly polymorphic human leukocyte antigens (HLAs) remain a barrier to their clinical applications. Here, we used a CRISPR/Cas9-mediated HLA-editing strategy to generate a variety of HLA homozygous-like hESC lines from pre-established hESC lines. We edited four pre-established HLA-heterozygous hESC lines and created a mini library of 14 HLA-edited hESC lines in which single HLA-A and HLA-B alleles and both HLA-DR alleles are disrupted. The HLA-edited hESC derivatives elicited both low T cell- and low NK cell-mediated immune responses. Our library would cover about 40% of the Asian-Pacific population. We estimate that HLA-editing of only 19 pre-established hESC lines would give rise to 46 different hESC lines to cover 90% of the Asian-Pacific population. This study offers an opportunity to generate an off-the-shelf HLA-compatible hESC bank, available for immune-compatible cell transplantation, without embryo destruction. Graphical Abstract.

Updates in uterine artery embolization for leiomyomas.

PURPOSE OF REVIEW: Uterine leiomyomas are a common condition estimated to affect 70-80% of reproductive-aged women. An evolving body of evidence continues to guide our understanding of various surgical and interventional treatment options, such as uterine artery embolization (UAE). This article provides an updated review of novel findings regarding UAE. RECENT FINDINGS: Despite an abundance of observational studies and several small randomized controlled trials, large scale long-term comparative efficacy studies are lacking. Although short-term outcomes continue to be favorable, recent trials show reoperation rate of up to 35% in 10 years and may raise some concerns regarding ovarian reserve, fertility and pregnancy outcomes. SUMMARY: UAE remains a safe and effective alternative to surgery in the management of leiomyomas. A deeper investigation into understanding this treatment's optimal use in various patient populations is needed.

Perioperative Antibiotic Use and Associated Infectious Outcomes at the Time of Myomectomy.

OBJECTIVE: To report the frequency of perioperative antibiotic use at time of myomectomy and associated risk of infectious outcomes. METHODS: We conducted a retrospective cohort study including all women who underwent any route of myomectomy from 2009 to 2016 at two academic hospitals in Boston, Massachusetts. Cases involving chromopertubation or conversion to hysterectomy were excluded from further analysis. Medical records were queried for the use or nonuse of perioperative antibiotics, as well as baseline patient factors and perioperative outcomes. Statistical analyses included univariate comparisons between treatment groups, as well as multivariable logistic regression analyses of infectious morbidity controlling for patient age, route of surgery, presence of high-risk factors, any intraoperative complication, myoma weight, and entrance into the endometrial cavity. Matched cohort analysis also was performed to confirm findings in the setting of underlying differences between groups. RESULTS: A total of 1,211 patients were included in the myomectomy cohort, 92.7% of whom received perioperative antibiotics at the time of surgery. Demographic characteristics were similar between the group that received and the group that did not receive antibiotics. The cases with antibiotic use were associated with longer operative times, higher estimated blood loss, and greater myoma burden. No difference was noted with regard to intraoperative or postoperative complications. Surgical site infection occurred more commonly in the group that did not receive antibiotics (2.9% vs 6.8% in the antibiotic and no-antibiotic groups, respectively; effect size 0.43, 95% CI 0.18-0.97 P=.04), representing a nearly fourfold increase in odds of any surgical site infection in the absence of perioperative antibiotic use (adjusted odds ratio 3.77, 95% CI 1.30-10.97, P=.015). CONCLUSION: A high frequency of antibiotic use was noted at time of myomectomy, despite lack of clear evidence supporting the practice. Patients who received perioperative antibiotics had fewer postoperative infectious outcomes and, in particular, experienced a lower incidence of surgical site infection.

The Trend, Feasibility, and Safety of Salpingectomy as a form of Permanent Sterilization.

STUDY OBJECTIVE: To assess the change in the rate of laparoscopic salpingectomy for sterilization after the release of the November 2013 Society of Gynecologic Oncology Clinical Practice Statement and the January 2015 American College of Obstetricians and Gynecologists Committee Opinion: Salpingectomy for Ovarian Cancer Prevention. We hypothesized there would be an increase in salpingectomy as a percentage of total laparoscopic sterilizations performed without an increase in complications when compared with conventional bilateral tubal ligation (BTL). DESIGN: A retrospective cohort study. SETTING: Four university-affiliated hospitals in Houston, TX, and New York, NY. PATIENTS: All women 21 years or older who underwent interval laparoscopic permanent sterilization between April 2013 and September 2016. INTERVENTIONS: Sterilization by bilateral salpingectomy or conventional tubal ligation. MEASUREMENTS AND MAIN RESULTS: There were 454 sterilization procedures identified; 60% were BTLs, whereas 40% were salpingectomies. The rate of use of salpingectomy significantly increased from 5% to 9% in 2013 to 2014 to 78% by 2016. There was no significant difference in intraoperative or postoperative complications or estimated blood loss. The mean procedure time was 54 minutes for salpingectomy compared with 45 minutes for BTL (p <.0001). Salpingectomy was more likely to require 3 ports compared with 2 ports for BTL (p <.0001). CONCLUSIONS: The Society of Gynecologic Oncology and the American College of Obstetricians and Gynecologists' support of salpingectomy for ovarian cancer prevention increased its use for sterilization. Based on this study, laparoscopic bilateral salpingectomy is a safe method of sterilization without an increase in perioperative risk compared with conventional tubal ligation. Physicians should incorporate these findings and implications when counseling patients regarding contraception and permanent sterilization.

Preterm Prelabor Rupture of Membranes: Outcomes with Expectant Management until 34 versus 35 Weeks.

OBJECTIVE: To evaluate outcomes with expectant management of preterm prelabor rupture of membranes (PROM) until 35 weeks versus immediate delivery at ≥34 weeks. STUDY DESIGN: This was a multicenter retrospective cohort study of singletons with preterm PROM at >20 weeks from 2011 through 2017. Groups were defined as expectant management until 35 weeks versus immediate delivery at ≥34 weeks. Primary outcome was composite neonatal morbidity: need for respiratory support, culture positive neonatal sepsis, or antibiotic administration for >72 hours. Univariate and general estimating equation models were used with p < 0.05 considered significant. RESULTS: A total of 280 mother-infant dyads were included. There was no difference in composite neonatal outcome in pregnancies managed with expectant management compared with immediate delivery (43.4 vs. 37.5%; p = 0.32). Those with expectant management had shorter length of neonatal intensive care unit (NICU) admission but higher rates of neonatal antibiotics for > 72 hours, endometritis, and histological chorioamnionitis. There were no cases of fetal demise, neonatal death, or maternal sepsis, and only three cases of neonatal sepsis. CONCLUSION: There is no difference in composite neonatal morbidity in pregnancies with preterm PROM managed with expectant management until 35 weeks as compared with immediate delivery at 34 weeks. Expectant management is associated with a decreased length of NICU admission but increased short-term infectious morbidity.

Laparoscopic Assessment to Determine the Likelihood of Achieving Optimal Cytoreduction in Patients Undergoing Primary Debulking Surgery for Ovarian, Fallopian Tube, or Primary Peritoneal Cancer.

OBJECTIVE: The objective of this study was to evaluate the safety and efficacy of laparoscopic assessment to determine the likelihood of achieving optimal cytoreduction (OC) in patients undergoing primary debulking surgery (PDS) for ovarian cancer. METHODS: All patients who underwent diagnostic laparoscopy and PDS at our institution from January 2008 to December 2013 were identified. We determined the likelihood of achieving optimal cytoreduction by laparoscopic assessment based on tumor site, pattern of spread, and disease burden. Sensitivity was defined as the number of patients who achieved optimal cytoreduction after laparoscopic assessment divided by the number of patients with disease deemed resectable by laparoscopy. RESULTS: We identified 55 patients during study period. Twenty-one of the 55 patients (38%) were early stage disease. Six (10.9%) patients had disease deemed unresectable and 49 (89.1%) had disease deemed resectable at the time of laparoscopy. OC was achieved in 48 of 49 (97.9%) patients. The sensitivity of laparoscopy in predicting OC was 98% (95% confidence interval, 89.3%-99.9%). The operation was completed laparoscopically in 23 of 49 patients (47%); in 26 of 49 (53%), PDS was performed by laparotomy. There were no port site metastases reported. The rate of postoperative complications was 16%. With a median follow-up of 30 months, the median overall survival was not reached and the 75th percentile for overall survival was 37 months. CONCLUSIONS: Laparoscopy was shown to have a high sensitivity in predicting OC and is a feasible tool in triaging patients with ovarian cancer. Laparoscopy is not associated with adverse surgical outcomes.

Interpreter training for medical students: pilot implementation and assessment in a student-run clinic.

BACKGROUND: Trained medical interpreters are instrumental to patient satisfaction and quality of care. They are especially important in student-run clinics, where many patients have limited English proficiency. Because student-run clinics have ties to their medical schools, they have access to bilingual students who may volunteer to interpret, but are not necessarily formally trained. METHODS: To study the feasibility and efficacy of leveraging medical student volunteers to improve interpretation services, we performed a pilot study at the student-run clinic at the Icahn School of Medicine at Mount Sinai. In each fall semester in 2012-2015, we implemented a 6-h course providing didactic and interactive training on medical Spanish interpreting techniques and language skills to bilingual students. We then assessed the impact of the course on interpreter abilities. RESULTS: Participants' comfort levels, understanding of their roles, and understanding of terminology significantly increased after the course (p < 0.05), and these gains remained several months later (p < 0.05) and were repeated in an independent cohort. Patients and student clinicians also rated participants highly (averages above 4.5 out of 5) on these measures in real clinical encounters. CONCLUSIONS: These findings suggest that a formal interpreter training course tailored for medical students in the setting of a student-run clinic is feasible and effective. This program for training qualified student interpreters can serve as a model for other settings where medical students serve as interpreters.

Pelvic recurrence of stage 1a well-differentiated endometrial carcinoma after 13 years: A case report.

A great majority of endometrial carcinoma recurrences are observed in high-risk patients and within the first 3 years of treatment. The relapse of endometrial carcinoma occurring more than 10 years after initial treatment has rarely been described. Initially diagnosed and treated for International Federation of Gynecology and Obstetrics (FIGO) stage 1a, grade 1 adenocarcinoma, our patient presented 13 years later with an isolated pelvic recurrence, demonstrating, to our knowledge, the longest disease-free interval with recurrence in the pelvis reported in literature. After surgical resection, the patient is being considered for enrollment in a clinical trial. Despite favorable prognostic features, it is possible to observe the recurrence of endometrial carcinoma even 5 years after surveillance and remission. Successful salvage therapies are available but may depend upon early diagnosis.