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Phosphatase and Tensin Homologue on chromosome Ten (PTEN) is a tumor suppressor and an antagonist of the phosphoinositide-3 kinase (PI3K) pathway. We identified a 576-amino acid translational variant of PTEN, termed PTEN-Long, that arises from an alternative translation start site 519 bp upstream of the ATG initiation sequence, adding 173 N-terminal amino acids to the normal PTEN open reading frame. PTEN-Long is a membrane permeable lipid phosphatase that is secreted from cells and can enter other cells. As an exogenous agent, PTEN-Long antagonized PI3K signaling and induced tumor cell death in vitro and in vivo. By providing a means to restore a functional tumor suppressor protein to tumor cells, PTEN-Long may have therapeutic uses.

Basal-like breast cancer (BBC) is a subtype of breast cancer with poor prognosis [1][2][3] . Inherited mutations of BRCA1, a cancer susceptibility gene involved in double-strand DNA break (DSB) repair, lead to breast cancers that are nearly always of the BBC subtype [3][4][5] ; however, the precise molecular lesions and oncogenic consequences of BRCA1 dysfunction are poorly understood. Here we show that heterozygous inactivation of the tumor suppressor gene Pten leads to the formation of basal-like mammary tumors in mice, and that loss of PTEN expression is significantly associated with the BBC subtype in human sporadic and BRCA1-associated hereditary breast cancers. In addition, we identify frequent gross PTEN mutations, involving intragenic chromosome breaks, inversions, deletions and micro copy number aberrations, specifically in BRCA1-deficient tumors. These data provide an example of a specific and recurrent Correspondence should be addressed to R.P. (rep15@columbia.edu). 14 These authors contributed equally to this work. AUTHOR CONTRIBUTIONS L.H.S., S.K.G.-S., R.P. and Å.B conceived and designed the study; L.H.S., S.K.G.-S., J.S., G.J., K.H., S.K., J.V.-C., H.O., T.S., L.M., S.P.E., H.H., R.P. and Å.B. collected the samples; L.H.S., K.L., M.J., L.M., T.L., M.S., J.I. and H.H. performed and analyzed immunohistochemistry experiments; L.H.S. and C.P. designed and performed methylation analyses; L.H.S., C.P., M.M. and K.H. performed nucleotide sequencing experiments; L.H.S., J.S., G.J. and K.H. performed and analyzed aCGH experiments; L.H.S., M.M.P., S.S. and V.V.V.S.M. designed and performed FISH experiments; L.H.S., S.K.G.-S. and M.K. performed statistical analyses; R.P. and Å.B. supervised the study; and L.H.S. wrote the paper with assistance from R.P. and Å.B. and input from all coauthors.Note: Supplementary information is available on the Nature Genetics website. [1][2][3][4][5] . Of these, basal-like breast cancer (BBC) comprises 10-20% of all breast cancer and is one of the subtypes with the worst prognosis 2-5 . The term BBC was coined because these tumors express cytokeratin markers typical of basally oriented epithelial cells of the normal mammary gland, such as CK5, CK14 and CK17 (refs. 1,3,5 ). In addition to having characteristic cytokeratin expression, BBCs are highly proliferative, poorly differentiated and genomically unstable, and they pose clinical challenges because they rarely express the three most common therapeutically targeted 'Achilles' heels' of breast cancer: the estrogen receptor (ER), progesterone receptor and HER2 receptor (refs. 1,3,5,7 ).Intriguingly, breast tumors initiated by an inherited mutation of BRCA1 are nearly always basal-like 3,5 . BRCA1 dysfunction is thought to be tumorigenic primarily owing to defective BRCA1-dependent DSB repair, which precipitates an accumulation of secondary mutations 10 ; however, only general genomic patterns at relatively low resolution have been described (reviewed in ref. 5 ). Despite these advances in delineating BBC, the molecu...

Summary PTEN (Phosphatase and tensin homolog on chromosome ten) is a tumor suppressor whose cellular regulation remains incompletely understood. We identified Phosphatidylinositol-3,4,5-trisphosphate RAC Exchanger 2a (P-REX2a) as a PTEN-interacting protein. P-REX2a mRNA was more abundant in cancer, and significantly increased in tumors with wild type PTEN that expressed an activated mutant of PIK3CA encoding the p110 subunit of phosphoinositide 3-kinase-α (PI3Kα). P-REX2a inhibited PTEN lipid phosphatase activity and stimulated the PI3K pathway only in the presence of PTEN. P-REX2a stimulated cell growth and cooperated with a PIK3CA mutant to promote growth factor-independent proliferation and transformation. Depletion of P-REX2a reduced amounts of phosphorylated AKT and growth in cell lines with intact PTEN. Thus P-REX2a is a component of the PI3K pathway that can antagonize PTEN in cancer cells.

In 2006, the IOM released a report citing the importance of "survivorship plans" to improve quality of life and care coordination for cancer survivors, but little has been done to evaluate their efficacy. Women with early-stage breast cancer were randomized within 6 weeks of completing adjuvant therapy to a survivorship intervention group (SI) or control group (CG). All subjects were given the NCI publication, "Facing Forward: Life after Cancer Treatment." The SI also met with a nurse/nutritionist to receive a treatment summary, surveillance, and lifestyle recommendations. Both groups completed questionnaires on the impact of cancer (IOC), patient satisfaction (FACIT-TS-PS), and assessment of survivor concerns (ASC) at baseline, 3 and 6 months. Within and between group t tests and linear regression analyses were performed. Among 126 women (60 CG, 66 SI), mean age was 54 years, 48 % were Hispanic, and the groups were well-balanced by baseline characteristics. No significant differences between the CG and SI on the FACIT-TS-PS or IOC at 3 and 6 months were seen. The ASC health worry subscale was lower (less worry) in the SI compared to CG (p = 0.02). At all time-points, Hispanic women had higher (worse) health worry (p = 0.0008), social-life interference (p = 0.009), and meaning of cancer scales (p = 0.0004), and more trust in medical professionals (p = 0.03) compared to non-Hispanic women. While the SI did not lead to significant improvements in most patient-reported outcomes, it was associated with decreased health worry. Future interventions should determine the most efficient and effective method for delivering survivorship care plans.

9520 Background: Signaling via LAG-3 and other T-cell inhibitory receptors (eg, PD-1) can lead to T-cell dysfunction and tumor immune escape. Simultaneous blockade of LAG-3 + PD-1 may synergistically restore T-cell activation and enhance antitumor immunity. In a phase 1/2a study, BMS-986016 (IgG4 mAb targeting LAG-3) ± nivo (IgG4 mAb targeting PD-1) demonstrated tolerability, peripheral T-cell activation, and preliminary clinical activity (NCT01968109; Lipson E, et al. J Immunother Cancer. 2016;4[s1]:173 [P232]). Here we describe preliminary efficacy of BMS-986016 + nivo in pts with MEL whose disease progressed on/after prior anti–PD-1/PD-L1 therapy, along with updated safety from all dose expansion pts. Methods: Pts with MEL must have had prior anti–PD-1/PD-L1 (± anti–CTLA-4 or BRAF/MEK inhibitors) and progressive disease (PD). Pts received BMS-986016 80 mg + nivo 240 mg IV Q2W. Primary objectives were safety and objective response rate (ORR; complete [CR] + partial [PR] response), disease control rate (DCR; CR + uCR + PR + uPR + stable disease [SD] > 12 wk), and duration of response (RECIST v1.1). Results: At data cutoff, 43 pts with MEL had been treated with BMS-986016 + nivo following PD on/after prior anti–PD-1/PD-L1 with known prior best responses of 1 CR, 9 PR, 12 SD, and 16 PD. Of the 43 pts, 30 (70%) also had prior anti–CTLA-4, 20 (47%) had ≥ 3 prior therapies, and 15 (35%) had BRAFmutations .In the 31 efficacy-evaluable pts to date, ORR was 16% (confirmed/unconfirmed) and DCR was 45% with benefit observed even in some pts refractory to prior anti–PD-1. Evaluations are ongoing for most pts, with median treatment duration of 10 wk for all 43 pts. Immunopathologic (eg, PD-1/PD-L1 and LAG-3 expression) and clinical characteristics of responders vs nonresponders will be presented. Any grade and grade 3/4 treatment-related AEs occurred in 46% and 9%, respectively, across all dose expansion pts (n = 129). Conclusion: Addition of BMS-986016 to nivolumab demonstrates encouraging initial efficacy in pts with MEL whose disease progressed on/after prior anti–PD-1/PD-L1 therapy, and a safety profile similar to nivolumab monotherapy. Clinical trial information: NCT01968109.

Background The PI3K/AKT pathway is activated through PIK3CA or AKT1 mutations and PTEN loss in breast cancer. We conducted a phase II trial with an allosteric AKT inhibitor MK-2206 in patients with advanced breast cancer who had tumors with PIK3CA/AKT1 mutations and/or PTEN loss/mutation. Methods The primary endpoint was objective response rate (ORR). Secondary endpoints were 6-month progression-free survival (6 m PFS), predictive and pharmacodynamic markers, safety, and tolerability. Patients had pre-treatment and on-treatment biopsies as well as collection of peripheral blood mononuclear cells (PBMC) and platelet-rich plasma (PRP). Next-generation sequencing, immunohistochemistry, and reverse phase protein arrays (RPPA) were performed. Results Twenty-seven patients received MK-2206. Eighteen patients were enrolled into the PIK3CA/AKT1 mutation arm (cohort A): 13 had PIK3CA mutations, four had AKT1 mutations, and one had a PIK3CA mutation as well as PTEN loss. ORR and 6 m PFS were both 5.6% (1/18), with one patient with HR+ breast cancer and a PIK3CA E542K mutation experiencing a partial response (on treatment for 36 weeks). Nine patients were enrolled on the PTEN loss/mutation arm (cohort B). ORR was 0% and 6 m PFS was 11% (1/9), observed in a patient with triple-negative breast cancer and PTEN loss. The study was stopped early due to futility. The most common adverse events were fatigue (48%) and rash (44%). On pre-treatment biopsy, PIK3CA and AKT1 mutation status was concordant with archival tissue testing. However, two patients with PTEN loss based on archival testing had PTEN expression on the pre-treatment biopsy. MK-2206 treatment was associated with a significant decline in pAKT S473 and pAKT T308 and PI3K activation score in PBMC and PRPs, but not in tumor biopsies. By IHC, there was no significant decrease in median pAKT S473 or Ki-67 staining, but a drop was observed in both responders. Conclusions MK-2206 monotherapy had limited clinical activity in advanced breast cancer patients selected for PIK3CA/AKT1 or PTEN mutations or PTEN loss. This may, in part, be due to inadequate target inhibition at tolerable doses in heavily pre-treated patients with pathway activation, as well as tumor heterogeneity and evolution in markers such as PTEN conferring challenges in patient selection. Trial registration ClinicalTrials.gov, NCT01277757 . Registered 13 January 2011. Electronic supplementary material The online version of this article (10.1186/s13058-019-1154-8) contains supplementary material, which is available to authorized users.

BACKGROUND There is a need for culturally-relevant nutrition programs targeted to underserved cancer survivors. OBJECTIVE To examine the effect of a culturally-based approach to dietary change on increasing fruit/vegetable intake and decreasing fat intake among Hispanic breast cancer (BC) survivors. DESIGN Participants were randomized to intervention (IG) and control (CG) groups. Diet recalls, detailed interviews, fasting blood, and anthropometric measures were collected at baseline, 3-, 6- and 12-months. PARTICIPANTS/SETTING Hispanic women (n=70) with stage 0-III BC who completed adjuvant treatment and lived in New York City were randomized between April 2011 and March 2012. INTERVENTION The IG (n=34) participated in ¡Cocinar Para Su Salud! (¡CPSS!), a culturally-based 9-session (24-hours over 12 weeks) intervention including nutrition education, cooking classes and food shopping field trips. The CG (n=36) received written dietary recommendations for BC survivors. MAIN OUTCOME MEASURES Change at 6 months in daily fruit/vegetable servings and % calories from total fat. STATISTICAL ANALYSES Linear regression models adjusted for stratification factors and estimated marginal means were used to compare changes in diet from baseline to 3- and 6-months. RESULTS Baseline characteristics: mean age 56.6 years (SD 9.7), mean time since diagnosis 3.4 years (SD 2.7), mean BMI 30.9 kg/m2 (SD 6.0), 62.9% with annual household income ≤$15,000, average daily servings of all fruits/vegetables 5.3 (targeted fruits/vegetables 3.7 servings excluding legumes/juices/starchy vegetables/fried foods) and 27.7% of daily calories from fat. Over 60% in the IG attended ≥7/9 classes with overall study retention of 87% retention at 6 months. At month 6, the IG compared to CG reported an increase in mean servings of fruits/vegetables from baseline (all fruits/vegetables: +2.0 vs. −0.1, P=0.005; targeted fruits/vegetables: +2.7 vs. +0.5, P=0.002) and a non-significant decrease in % calories from fat (−7.5% vs. −4.4%, P=0.23) and weight (−2.5kg vs. +3.8kg, P=0.22). CONCLUSIONS ¡CPSS! was effective at increasing short-term fruit/vegetable intake in a diverse population of Hispanic BC survivors.