Radiation therapy for low- and high-risk perineural invasion in head and neck cutaneous squamous cell carcinoma: Clinical outcomes and patterns of failure.

BACKGROUND: Perineural invasion (PNI) in head and neck squamous cell carcinoma (HNSCC) portends poor prognosis. Extent of treatment of nerve pathways with varying degrees of PNI and patterns of failure following elective neural radiotherapy (RT) remain unclear. METHODS: Retrospective review of HNSCC patients with high-risk (clinical/gross, large-nerve, extensive) or low-risk (microscopic/focal) PNI who underwent curative-intent treatment from 2010 to 2021. RESULTS: Forty-four patients (mean follow-up 22 months; 59% high-risk, 41% low-risk PNI) were included. Recurrence following definitive treatment occurred in 31% high-risk and 17% low-risk PNI patients. Among high-risk patients, 69% underwent surgery with post-operative RT and 46% underwent elective neural RT. Local control (83% low-risk vs. 75% high-risk), disease-free, and overall survival did not differ between groups. CONCLUSIONS: High local control rates were achieved in high-risk PNI patients treated with adjuvant or primary RT, including treatment of both involved and uninvolved, communicating cranial nerves, with few failures in electively treated regions.

Assessing the Clinical Utility of the Early Postoperative Pharyngogram in Hypopharyngeal Surgery for Dysphagia.

OBJECTIVES/HYPOTHESIS: To evaluate the clinical utility of postoperative contrast x-ray pharyngograms (XRP) for detecting pharyngoesophageal leaks following hypopharyngeal dysphagia surgery. STUDY DESIGN: Retrospective cohort study. METHODS: Medical records were reviewed of patients undergoing endoscopic (E-) or open (O-) Zenker's diverticulectomy (-ZD) with cricopharyngeal myotomy (-CPM) and CPM alone from 2008 to 2020 at one academic institution. Exclusion criteria were patients who were fed enterally or underwent repair of epiphrenic diverticula or O-CPM during laryngectomy. XRP clinical indication, impact on clinical care, and factors associated with use patterns were examined using descriptive statistics and logistic regression (LR). RESULTS: Of 152 subjects, 52% underwent O-ZD, 30% O-CPM, 15% E-ZD, and 3% E-CPM. An XRP was ordered for 65% of subjects, mostly routinely (94%). Among the four clinically apparent leaks observed in this cohort, early postoperative XRP confirmed one. It did not identify any clinically silent leaks. In univariate LR, undergoing XRP was associated with increasing day of diet advancement (odds ratio [OR] 4.7, 95% confidence interval [CI] 2.5-10.5) and hospital stay duration (OR 3.2, 95% CI 2.1-5.2), as well as surgeon specialty of otolaryngology compared to general surgery (OR 12.8, 95% CI 4.8-40.8) and procedure sub-type (O-CPM: OR 0.03, 95% CI 0.002-0.16). In multivariate LR, the following variables were significantly associated with XRP use: hospital stay (OR 1.7; 95% CI 1.1-3.0), otolaryngology (OR 105; 95% CI 15.4-2193), O-CPM (OR 0.03; 95% CI 0.002-0.16), and E-CPM (OR 0.04, 95% CI 0.002-0.60). CONCLUSIONS: Prospective, multi-institutional studies are needed to confirm the low clinical utility we observed of early, postoperative XRP following hypopharyngeal surgery for dysphagia. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:272-277, 2022.

Safety and Predictors of 30-Day Adverse Events of Laryngeal Framework Surgery: An Analysis of ACS-NSQIP data.

OBJECTIVES/HYPOTHESIS: To characterize and identify predictors of 30-day adverse events in patients undergoing laryngeal framework surgery (LFS). STUDY DESIGN: This study is a retrospective analysis of the National Surgical Quality Improvement dataset. METHODS: LFS cases were identified from the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database from 2008 to 2018. Demographic variables, patient comorbidities, and perioperative outcomes (any adverse event, 30-day readmission, 30-day reoperation, and unplanned intubation) were extracted. Patient-specific and surgery-specific factors associated with perioperative adverse events were examined using descriptive statistics and univariate logistic regression (LR). RESULTS: Of 283 patients who underwent LFS, 225 underwent laryngoplasty medialization, 56 underwent laryngoplasty medialization with arytenoidectomy or arytenoidopexy via an external approach, and 2 underwent local myocutaneous or fasciocutaneous advancement flap along with laryngoplasty. Medical comorbidities were present in 33.6% of patients and 57.9% were American Society of Anesthesiologists (ASA) Class III/IV (57.9%). LFS was performed as same-day surgery in 30.7% of cases. Fourteen patients (4.9%) suffered an adverse condition within 30 days following surgery. In univariate LR, ASA Class III or IV (odds ratio [OR] 4.6, 95% confidence interval [CI] 1.2-30.1) was the only predictor associated with any adverse event. Arytenoid adduction (AA) was associated with increased risk of reoperation within 30 days of the initial surgery (OR 6.4, 95% CI 1.0-49). CONCLUSIONS: LFS is a generally safe procedure with infrequent perioperative adverse events. In the ACS-NSQIP database, ASA classification of III or IV was associated with a higher risk for any 30-day adverse event and AA was associated with a higher risk for 30-day reoperation. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:1414-1420, 2022.

A diverse collection of B cells responded to HIV infection in infant BG505.

Increasing evidence suggests infants develop unique neutralizing antibody (nAb) responses to HIV compared to adults. Here, we dissected the nAb response of an infant whose virus is in clinical trials as a vaccine immunogen, with a goal of characterizing the broad responses in the infant to this antigen. We isolated 73 nAbs from infant BG505 and identified a large number of clonal families. Twenty-six antibodies neutralized tier 2 viruses-in some cases, viruses from the same clade as BG505, and in others, a different clade, although none showed notable breadth. Several nAbs demonstrated antibody-dependent cellular cytotoxicity activity and targeted the V3 loop. These findings suggest an impressive polyclonal response to HIV infection in infant BG505, adding to the growing evidence that the nAb response to HIV in infants is polyclonal-a desirable vaccine response to a rapidly evolving virus like HIV.

Oncologic outcomes of human papillomavirus-associated oropharynx carcinoma treated with surgery alone: A 12-institution study of 344 patients.

BACKGROUND: The oncologic outcomes of surgery alone for patients with American Joint Committee on Cancer 7th edition (AJCC 7th) pN2a and pN2b human papillomavirus-associated oropharynx squamous cell carcinoma (HPV+OPSCC) are not clear. METHODS: The authors performed a 12-institution retrospective study of 344 consecutive patients with HPV+OPSCC (AJCC 7th pT0-3 N3 M0) treated with surgery alone with 6 months or more of follow-up using univariate and multivariate analyses. RESULTS: The 2-year outcomes for the entire cohort were 91% (182 of 200) disease-free survival (DFS), 100% (200 of 200) disease-specific survival (DSS), and 98% (200 of 204) overall survival (OS). The 18 recurrences within 2 years were 88.9% (16 of 18) local and/or regional recurrences and 11.1% (2 of 18) distant metastases. Recurrences were not significantly associated with smoking, pT stage, or pN stage. The 16 patients with locoregional recurrences within 2 years all underwent successful salvage treatments (median follow-up after salvage: 13.1 months), 43.8% (7 of 16) of whom underwent salvage surgery alone for a 2-year overall salvage radiation need of 4.5% (9 of 200). The 2-year outcomes for the 59 evaluable patients among the 109 AJCC 7th pT0-2 N2a-N2b patients with 1 to 3 pathologic lymph nodes (LNs) were as follows: local recurrence, 3.4% (2 of 59); regional recurrence, 8.4% (5 of 59); distant metastases, 0%; DFS, 88.1% (52 of 59); DSS, 100% (59 of 59); OS, 96.7% (59 of 61); and salvage radiation, 5.1% (3 of 59). CONCLUSIONS: With careful selection, surgery alone for AJCC 7th pT0-T2N0-N2b HPV+OPSCC with zero to 3 pathologic LNs without perineural invasion, extranodal extension, or positive margins results in high DFS, DSS, OS, and salvage treatment success. Because of the short-term follow-up, these data support further investigation of treatment de-escalation in this population.

A Guide to Creating a Gender-Affirming Environment Through a Community Lens Approach.

Lesbian, gay, bisexual, transgender, queer, and intersex (LGBTQI+) communities continue to experience health care disparities and inequities due to a shortage of trained health care providers, despite increased attention to LGBTQI+ health care. Many settings are starting to integrate gender-affirming health care and focus training on the provision of hormonal therapy, medications to decrease the risk of human immunodeficiency acquisition, and referrals to surgeons for affirming surgical procedures. A vital component to providing inclusive and comprehensive care involves community input, engagement, and buy-in. This article provides a framework for comprehensive gender-affirming health care through the lens of community involvement and outreach.

A Novel Curriculum for Medical Student Training in LGBTQ Healthcare: A Regional Pathway Experience.

BACKGROUND: Lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals face considerable health disparities, often due to a lack of LGBTQ-competent care. Such disparities and lack of access to informed care are even more staggering in rural settings. As the state medical school for the Washington, Wyoming, Alaska, Montana, and Idaho (WWAMI) region, the University of Washington School of Medicine (UWSOM) is in a unique position to train future physicians to provide healthcare that meets the needs of LGBTQ patients both regionally and nationally. OBJECTIVE: To describe our methodology of developing a student-driven longitudinal, region-wide curriculum to train medical students to provide high-quality care to LGBTQ patients. METHODS: A 4-year LGBTQ Health Pathway was developed and implemented as a student-led initiative at the UWSOM. First- and second-year medical students at sites across the WWAMI region are eligible to apply. Accepted Pathway students complete a diverse set of pre-clinical and clinical components: online modules, didactic courses, longitudinal community service/advocacy work, a scholarly project, and a novel clinical clerkship in LGBTQ health developed specifically for this Pathway experience. Students who complete all requirements receive a certification of Pathway completion. This is incorporated into the Medical Student Performance Evaluation as part of residency applications. RESULTS: The LGBTQ Health Pathway is currently in its fourth year. A total of 43 total students have enrolled, of whom 37.3% are based in the WWAMI region outside of Seattle. Pathway students have completed a variety of scholarly projects on LGBTQ topics, and over 1000 hours of community service/advocacy. The first cohort of 8 students graduated with a certificate of Pathway completion in spring 2020. CONCLUSIONS: The LGBTQ Health Pathway at UWSOM is a novel education program for motivated medical students across the 5-state WWAMI region. The diverse milestones, longitudinal nature of the program, focus on rural communities, and opportunities for student leadership are all strengths and unique aspects of this program. The Pathway curriculum and methodology described here serve as a model for student involvement and leadership in medical education. This program enables medical students to enhance their training in the care of LGBTQ patients and provides a unique educational opportunity for future physicians who strive to better serve LGBTQ populations.

Case of Esophageal Perforation and Repair with a Supraclavicular Artery Island Fascial Flap 15 Years After Anterior Spine Surgery.

BACKGROUND: Esophageal perforation represents a rare but potentially life-threatening complication of an anterior cervical diskectomy and fusion (ACDF). Delayed presentations of esophageal perforation more than 10 years following surgery are exceedingly rare and difficult to diagnose. Here, we discuss the case of an 80-year-old man who presented to the emergency department with progressive dysphagia 15 years after his ACDF. CASE DESCRIPTION: While prior outpatient workup was suggestive of a diverticulum, there was no evidence of esophageal perforation. Progressive symptoms and repeat imaging on admission were suggestive of retropharyngeal phlegmon. Operative esophagoscopy revealed that the spinal hardware had eroded through the posterior wall of the esophagus, creating a traction diverticulum. The hardware was removed, and the esophageal perforation was closed primarily and buttressed with vascularized tissue from a supraclavicular artery island fascial flap. CONCLUSIONS: This case emphasizes the importance of considering an esophageal perforation in patients who present with dysphagia at any interval following an ACDF, even in the extremely delayed setting. Furthermore, this is the first report, to the best of our knowledge, using a supraclavicular artery island fascial flap to reconstruct an esophageal perforation following an ACDF, and we introduce a novel strategy for managing these complicated injuries.

The Robust Restriction of Zika Virus by Type-I Interferon in A549 Cells Varies by Viral Lineage and Is Not Determined by IFITM3.

Type-I interferon (IFN-I) is a major antiviral host response but its impact on Zika virus (ZIKV) replication is not well defined, particularly as it relates to different circulating strains. Interferon stimulated genes (ISGs) that inhibit ZIKV, such as IFITM3, have been identified largely using overexpression studies. Here, we tested whether diverse ZIKV strains differed in their susceptibility to IFN-I-mediated restriction and the contribution of IFITM3 to this restriction. We identified a robust IFN-I-mediated antiviral effect on ZIKV replication (>100-fold reduction) in A549 cells, a commonly used cell line to study ZIKV replication. The extent of inhibition depended on the IFN-I type and the virus strain tested. Viruses from the American pathogenic outbreak were more sensitive to IFNα (p = 0.049) and IFNß (p = 0.09) than African-lineage strains, which have not been linked to severe pathogenesis. Knocking out IFITM3 expression did not dampen the IFN-I antiviral effect and only high overexpression of IFITM3 led to ZIKV inhibition. Moreover, IFITM3 expression levels in different cells were not associated with IFN-mediated ZIKV inhibition. Taken together, our findings indicate that there is a robust IFN-I-mediated antiviral effect on ZIKV infection, particularly for American viruses, that is not due to IFITM3. A549 cells, which are a commonly used cell line to study ZIKV replication, present an opportunity for the discovery of novel antiviral ISGs against ZIKV.

Zika Virus Circulates at Low Levels in Western and Coastal Kenya.

BACKGROUND: Zika virus (ZIKV) was discovered over 70 years ago in East Africa, but little is known about its circulation and pathogenesis there. METHODS: We screened 327 plasma samples collected 2-12 months after febrile illness in Western and coastal Kenya (1993-2016) for binding and neutralizing antibodies to distinguish ZIKV and dengue virus (DENV) responses, which we found were common in coastal Kenya. RESULTS: Two cases had durable ZIKV-specific antibodies and 2 cases had ZIKV antibodies at similar levels as DENV antibodies. CONCLUSIONS: This suggests low-level ZIKV circulation in Kenya over 2 decades and sets a baseline for future surveillance efforts in East Africa.

Diversity and Function of Maternal HIV-1-Specific Antibodies at the Time of Vertical Transmission.

Infants of HIV-positive mothers can acquire HIV infection by various routes, but even in the absence of antiviral treatment, the majority of these infants do not become infected. There is evidence that maternal antibodies provide some protection from infection, but gestational maternal antibodies have not yet been characterized in detail. One of the most studied vertically infected infants is BG505, as the virus from this infant yielded an Envelope protein that was successfully developed as a stable trimer. Here, we isolated and characterized 39 HIV-specific neutralizing monoclonal antibodies (nAbs) from MG505, the mother of BG505, at a time point just prior to vertical transmission. These nAbs belonged to 21 clonal families and employed a variety of VH genes. Many were specific for the HIV-1 Env V3 loop, and this V3 specificity correlated with measurable antibody-dependent cellular cytotoxicity (ADCC) activity. The isolated nAbs did not recapitulate the full breadth of heterologous or autologous virus neutralization by contemporaneous plasma. Notably, we found that the V3-targeting nAb families neutralized one particular maternal Env variant, even though all tested variants had low V3 sequence diversity and were measurably bound by these nAbs. None of the nAbs neutralized BG505 transmitted virus. Furthermore, the MG505 nAb families were found at relatively low frequencies within the maternal B cell repertoire; all were less than 0.25% of total IgG sequences. Our findings illustrate an example of the diversity of HIV-1 nAbs within one mother, cumulatively resulting in a collection of antibody specificities that can contribute to the transmission bottleneck.IMPORTANCE Mother-to-child-transmission of HIV-1 offers a unique setting in which maternal antibodies both within the mother and passively transferred to the infant are present at the time of viral exposure. Untreated HIV-exposed human infants are infected at a rate of 30 to 40%, meaning that some infants do not get infected despite continued exposure to virus. Since the potential of HIV-specific immune responses to provide protection against HIV is a central goal of HIV vaccine design, understanding the nature of maternal antibodies may provide insights into immune mechanisms of protection. In this study, we isolated and characterized HIV-specific antibodies from the mother of an infant whose transmitted virus has been well studied.

Identification of HIV gp41-specific antibodies that mediate killing of infected cells.

Antibodies that mediate killing of HIV-infected cells through antibody-dependent cellular cytotoxicity (ADCC) have been implicated in protection from HIV infection and disease progression. Despite these observations, these types of HIV antibodies are understudied compared to neutralizing antibodies. Here we describe four monoclonal antibodies (mAbs) obtained from one individual that target the HIV transmembrane protein, gp41, and mediate ADCC activity. These four mAbs arose from independent B cell lineages suggesting that in this individual, multiple B cell responses were induced by the gp41 antigen. Competition and phage peptide display mapping experiments suggested that two of the mAbs target epitopes in the cysteine loop that are highly conserved and a common target of HIV gp41-specific antibodies. The amino acid sequences that bind these mAbs are overlapping but distinct. The two other mAbs were competed by mAbs that target the C-terminal heptad repeat (CHR) and the fusion peptide proximal region (FPPR) and appear to both target a similar unique conformational epitope. These gp41-specific mAbs mediated killing of infected cells that express high levels of Env due to either pre-treatment with interferon or deletion of vpu to increase levels of BST-2/Tetherin. They also mediate killing of target cells coated with various forms of the gp41 protein, including full-length gp41, gp41 ectodomain or a mimetic of the gp41 stump. Unlike many ADCC mAbs that target HIV gp120, these gp41-mAbs are not dependent on Env structural changes associated with membrane-bound CD4 interaction. Overall, the characterization of these four new mAbs that target gp41 and mediate ADCC provides evidence for diverse gp41 B cell lineages with overlapping but distinct epitopes within an individual. Such antibodies that can target various forms of envelope protein could represent a common response to a relatively conserved HIV epitope for a vaccine.

Treatment of Tonsillar Carcinoma following Nononcologic Tonsillectomy: Efficacy of Transoral Robotic Revision Tonsillectomy.

OBJECTIVE: To evaluate whether transoral robotic surgery (TORS) is a suitable treatment approach for patients diagnosed with tonsillar carcinoma after a standard palatine tonsillectomy. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary care medical center. SUBJECTS AND METHODS: Patients who underwent TORS at the University of Washington from 2010 to 2017 (n = 150) were identified. All patients who were diagnosed with tonsillar carcinoma following a nononcologic tonsillectomy and subsequently underwent TORS radical tonsillectomy were included (n = 14). Tumor stage-matched subjects (n = 44) were included who did not undergo standard tonsillectomy prior to TORS. Our primary outcome was final margin status. Secondary outcomes were presence of residual tumor, receipt and dose of postoperative adjuvant therapy, disease-free survival (DFS), and disease-specific survival. Patients with <6 months of follow-up following definitive treatment were excluded from survival analyses. RESULTS: Final margin status was clear in all subjects. Residual tumor was not identified in 13 of 14 (92.9%) prior-tonsillectomy subjects following TORS radical tonsillectomy. Seven of 14 (50%) prior-tonsillectomy subjects and 12 of 44 (27.3%) TORS-matched subjects did not require adjuvant therapy due to favorable pathology. Among subjects who received post-TORS radiation therapy (RT) at our institution, RT dose reduction was achieved in 3 of 4 (75%) prior-tonsillectomy subjects and 21 of 24 (87.5%) TORS-matched subjects. Ten of 14 (71.4%) prior-tonsillectomy subjects and 31 of 44 (70.5%) TORS-matched subjects avoided post-TORS chemotherapy. DFS was not significantly different ( P = .87) between prior-tonsillectomy and TORS-matched groups, and no subjects died of related disease. CONCLUSIONS: Patients diagnosed with tonsillar carcinoma following a prior nononcologic standard palatine tonsillectomy are suitable candidates for revision surgery with TORS radical tonsillectomy.

Genome sequencing in a case of Niemann-Pick type C.

Adult-onset Niemann-Pick disease type C (NPC) is an infrequent presentation of a rare neurovisceral lysosomal lipid storage disorder caused by autosomal recessive mutations in NPC1 (∼95%) or NPC2 (∼5%). Our patient was diagnosed at age 33 when he presented with a 10-yr history of difficulties in judgment, concentration, speech, and coordination. A history of transient neonatal jaundice and splenomegaly with bone marrow biopsy suggesting a lipid storage disorder pointed to NPC; biochemical ("variant" level cholesterol esterification) and ultrastructural studies in adulthood confirmed the diagnosis. Genetic testing revealed two different missense mutations in the NPC1 gene-V950M and N1156S. Symptoms progressed over >20 yr to severe ataxia and spasticity, dementia, and dysphagia with aspiration leading to death. Brain autopsy revealed mild atrophy of the cerebrum and cerebellum. Microscopic examination showed diffuse gray matter deposition of balloon neurons, mild white matter loss, extensive cerebellar Purkinje cell loss with numerous "empty baskets," and neurofibrillary tangles predominantly in the hippocampal formation and transentorhinal cortex. We performed whole-genome sequencing to examine whether the patient harbored variants outside of the NPC1 locus that could have contributed to his late-onset phenotype. We focused analysis on genetic modifiers in pathways related to lipid metabolism, longevity, and neurodegenerative disease. We identified no rare coding variants in any of the pathways examined nor was the patient enriched for genome-wide association study (GWAS) single-nucleotide polymorphisms (SNPs) associated with longevity or altered lipid metabolism. In light of these findings, this case provides support for the V950M variant being sufficient for adult-onset NPC disease.

Structural and Functional Analysis of the Allosteric Inhibition of IRE1α with ATP-Competitive Ligands.

The accumulation of unfolded proteins under endoplasmic reticulum (ER) stress leads to the activation of the multidomain protein sensor IRE1α as part of the unfolded protein response (UPR). Clustering of IRE1α lumenal domains in the presence of unfolded proteins promotes kinase trans-autophosphorylation in the cytosol and subsequent RNase domain activation. Interestingly, there is an allosteric relationship between the kinase and RNase domains of IRE1α, which allows ATP-competitive inhibitors to modulate the activity of the RNase domain. Here, we use kinase inhibitors to study how ATP-binding site conformation affects the activity of the RNase domain of IRE1α. We find that diverse ATP-competitive inhibitors of IRE1α promote dimerization and activation of RNase activity despite blocking kinase autophosphorylation. In contrast, a subset of ATP-competitive ligands, which we call KIRAs, allosterically inactivate the RNase domain through the kinase domain by stabilizing monomeric IRE1α. Further insight into how ATP-competitive inhibitors are able to divergently modulate the RNase domain through the kinase domain was gained by obtaining the first structure of apo human IRE1α in the RNase active back-to-back dimer conformation. Comparison of this structure with other existing structures of IRE1α and integration of our extensive structure activity relationship (SAR) data has led us to formulate a model to rationalize how ATP-binding site ligands are able to control the IRE1α oligomeric state and subsequent RNase domain activity.

Synthesis and structure­activity relationships of small molecule inhibitors of the simian virus 40 T antigen oncoprotein, an anti-polyomaviral target.

Polyomavirus infections are common and relatively benign in the general human population but can become pathogenic in immunosuppressed patients. Because most treatments for polyomavirusassociated diseases nonspecifically target DNA replication, existing treatments for polyomavirus infection possess undesirable side effects. However, all polyomaviruses express Large Tumor Antigen (T Ag), which is unique to this virus family and may serve as a therapeutic target. Previous screening of pyrimidinone­peptoid hybrid compounds identified MAL2-11B and a MAL2-11B tetrazole derivative as inhibitors of viral replication and T Ag ATPase activity (IC50 of ~20-50 µM. To improve upon this scaffold and to develop a structure­activity relationship for this new class of antiviral agents, several iterative series of MAL2-11B derivatives were synthesized. The replacement of a flexible methylene chain linker with a benzyl group or, alternatively, the addition of an ortho-methyl substituent on the biphenyl side chain in MAL2-11B yielded an IC50 of 50 µM, which retained antiviral activity. After combining both structural motifs, a new lead compound was identified that inhibited T Ag ATPase activity with an IC50 of 50 µM. We suggest that the knowledge gained from the structure­activity relationship and a further refinement cycle of the MAL2-11B scaffold will provide a specific, novel therapeutic treatment option for polyomavirus infections and their associated diseases.

Identification of an allosteric small-molecule inhibitor selective for the inducible form of heat shock protein 70.

Inducible Hsp70 (Hsp70i) is overexpressed in a wide spectrum of human tumors, and its expression correlates with metastasis, poor outcomes, and resistance to chemotherapy in patients. Identification of small-molecule inhibitors selective for Hsp70i could provide new therapeutic tools for cancer treatment. In this work, we used fluorescence-linked enzyme chemoproteomic strategy (FLECS) to identify HS-72, an allosteric inhibitor selective for Hsp70i. HS-72 displays the hallmarks of Hsp70 inhibition in cells, promoting substrate protein degradation and growth inhibition. Importantly, HS-72 is selective for Hsp70i over the closely related constitutively active Hsc70. Studies with purified protein show HS-72 acts as an allosteric inhibitor, reducing ATP affinity. In vivo HS-72 is well-tolerated, showing bioavailability and efficacy, inhibiting tumor growth and promoting survival in a HER2+ model of breast cancer. The HS-72 scaffold is amenable to resynthesis and iteration, suggesting an ideal starting point for a new generation of anticancer therapeutics targeting Hsp70i.