Impact of routine mismatch repair screening on genetic counseling and surgical management in colorectal cancer patients.

BACKGROUND: Mismatch repair (MMR) deficiency in colorectal cancer (CRC) should prompt consideration of genetic counseling (GC) as a Lynch syndrome (LS) diagnosis may have several implications for the patient and family. The study aims were to examine how routine MMR testing influences the rate of GC and surgical resection extent. METHODS: A single-institution retrospective review was performed on CRC specimens (including colonoscopic biopsies) routinely screened for MMR deficiency from 2012 to 2018. MLH1-deficient cancers with mutated BRAF or MLH1-promoter hypermethylation were excluded. RESULTS: MMR deficiency was identified in 295 of 1139 CRC specimens. After exclusions, 57 patients remained. Forty-two patients (74%) were identified preoperatively, and 35 (83%) were referred to GC: 16 were seen preoperatively, 9 postoperatively. Eight patients were diagnosed with Lynch syndrome (LS) preoperatively: 2 had no resection, 2 underwent segmental resection and 4 underwent extended resection. CONCLUSIONS: Most MMR-deficient patients were identified and referred to GC preoperatively, though not all were seen. Of the preoperatively diagnosed LS patients, half underwent extended resection. Barriers to GC and decision-making around resection extent bears further study.

Male sex, ostomy, infection, and intravenous fluids are associated with increased risk of postoperative ileus in elective colorectal surgery.

BACKGROUND: Postoperative ileus is a common and costly complication after elective colorectal surgery. Effects of intravenous fluid administration remain controversial, and the effect of ostomy construction has not been fully evaluated. Various restrictive intravenous fluid protocols may adversely affect renal function. We aimed to investigate the impact of intestinal reconstruction and intravenous fluid on ileus and renal function after colorectal resection under an enhanced recovery protocol. METHODS: A retrospective study of a prospectively maintained institutional database for a tertiary academic medical center following National Surgical Quality Improvement Program standards was reviewed, analyzing elective colorectal resections performed under enhanced recovery protocol from 2015 to 2018. Postoperative ileus was defined as nasogastric decompression, nil per os >3 days postoperatively, or nasogastric tube insertion. Patients with and without ileus were compared. Intravenous fluid and different anastomoses and ostomies were investigated. Acute kidney injury was a secondary outcome, due to the potential of renal damage with restriction of intravenous fluid volume during and after surgery and controversy in current literature in this matter. RESULTS: Postoperative ileus occurred in 18.5% of patients (n = 464). Male sex (odds ratio 1.97, 95% confidence interval 1.12-3.52) and postoperative infection (odds ratio 2.13, 95% confidence interval 1.03-4.35) were associated with ileus. Compared to colorectal anastomosis, ileostomy/ileorectal anastomosis had the highest risk of ileus (odds ratio 4.9, 95% confidence interval 2.33-11.3), colostomy second highest (odds ratio 3.3, 95% confidence interval 1.35-8.39), while ileocolic anastomosis did not significantly differ (odds ratio 2.06, 95% confidence interval 0.69-5.85) on multivariate analysis. Each liter of intravenous fluid within the first 72 hours significantly correlated with postoperative ileus (odds ratio 1.41, 95% confidence interval 1.27-1.59). Rates of acute kidney injury did not differ (P = .18). CONCLUSION: Each additional liter of intravenous fluid given in the first 72 hours increased the risk of postoperative ileus 1.4-fold. There is substantially higher risk of ileus with male sex, infection, ileostomy/ileorectal anastomosis, and colostomy. Judicious use of intravenous fluid, as described in our enhanced recovery protocol, is not detrimental for renal function in the setting of normal baseline.

AP-2α-Mediated Activation of E2F and EZH2 Drives Melanoma Metastasis.

In melanoma metastasis, the role of the AP-2α transcription factor, which is encoded by TFAP2A, is controversial as some findings have suggested tumor suppressor activity while other studies have shown high TFAP2A expression in node-positive melanoma associated with poor prognosis. Here we demonstrate that AP-2α facilitates melanoma metastasis through transcriptional activation of genes within the E2F pathway including EZH2. A BioID screen found that AP-2α interacts with members of the nucleosome remodeling and deacetylase (NuRD) complex. Loss of AP-2α removed activating chromatin marks in the promoters of EZH2 and other E2F target genes through activation of the NuRD repression complex. In melanoma cells, treatment with tazemetostat, an FDA-approved and highly specific EZH2 inhibitor, substantially reduced anchorage-independent colony formation and demonstrated heritable antimetastatic effects, which were dependent on AP-2α. Single-cell RNA sequencing analysis of a metastatic melanoma mouse model revealed hyperexpansion of Tfap2a High/E2F-activated cell populations in transformed melanoma relative to progenitor melanocyte stem cells. These findings demonstrate that melanoma metastasis is driven by the AP-2α/EZH2 pathway and suggest that AP-2α expression can be used as a biomarker to predict responsiveness to EZH2 inhibitors for the treatment of advanced melanomas. SIGNIFICANCE: AP-2α drives melanoma metastasis by upregulating E2F pathway genes including EZH2 through inhibition of the NuRD repression complex, serving as a biomarker to predict responsiveness to EZH2 inhibitors.

AP-2γ Is Required for Maintenance of Multipotent Mammary Stem Cells.

Mammary gland ductal morphogenesis depends on the differentiation of mammary stem cells (MaSCs) into basal and luminal lineages. The AP-2γ transcription factor, encoded by Tfap2c, has a central role in mammary gland development but its effect in mammary lineages and specifically MaSCs is largely unknown. Here, we utilized an inducible, conditional knockout of Tfap2c to elucidate the role of AP-2γ in maintenance and differentiation of MaSCs. Loss of AP-2γ in the basal epithelium profoundly altered the transcriptomes and decreased the number of cells within several clusters of mammary epithelial cells, including adult MaSCs and luminal progenitors. AP-2γ regulated the expression of genes known to be required for mammary development, including Cebpb, Nfkbia, and Rspo1. As a result, AP-2γ-deficient mice exhibited repressed mammary gland ductal outgrowth and inhibition of regenerative capacity. The findings demonstrate that AP-2γ can regulate development of mammary gland structures potentially regulating maintenance and differentiation of multipotent MaSCs.

AP-2α Regulates S-Phase and Is a Marker for Sensitivity to PI3K Inhibitor Buparlisib in Colon Cancer.

Activating protein 2 alpha (AP-2α; encoded by TFAP2A) functions as a tumor suppressor and influences response to therapy in several cancer types. We aimed to characterize regulation of the transcriptome by AP-2α in colon cancer. CRISPR-Cas9 and short hairpin RNA were used to eliminate TFAP2A expression in HCT116 and a panel of colon cancer cell lines. AP-2α target genes were identified with RNA sequencing and chromatin immunoprecipitation sequencing. Effects on cell cycle were characterized in cells synchronized with aphidicolin and analyzed by FACS and Premo FUCCI. Effects on invasion and tumorigenesis were determined by invasion assay, growth of xenografts, and phosphorylated histone H3 (PHH3). Knockout of TFAP2A induced significant alterations in the transcriptome including repression of TGM2, identified as a primary gene target of AP-2α. Loss of AP-2α delayed progression through S-phase into G2-M and decreased phosphorylation of AKT, effects that were mediated through regulation of TGM2. Buparlisib (BKM120) repressed in vitro invasiveness of HCT116 and a panel of colon cancer cell lines; however, loss of AP-2α induced resistance to buparlisib. Similarly, buparlisib repressed PHH3 and growth of tumor xenografts and increased overall survival of tumor-bearing mice, whereas, loss of AP-2α induced resistance to the effect of PI3K inhibition. Loss of AP-2α in colon cancer leads to prolonged S-phase through altered activation of AKT leading to resistance to the PI3K inhibitor, Buparlisib. The findings demonstrate an important role for AP-2α in regulating progression through the cell cycle and indicates that AP-2α is a marker for response to PI3K inhibitors. IMPLICATIONS: AP-2α regulated cell cycle through the PI3K cascade and activation of AKT mediated through TGM2. AP-2α induced sensitivity to Buparlisib/BKM120, indicating that AP-2α is a biomarker predictive of response to PI3K inhibitors.

Teaching Patient-Related Communication to Surgical Residents in Brief Training Sessions.

OBJECTIVE: Effective provider-patient communication has several benefits; however, few surgical residency programs have communication training and surgical residents have limited time for education. We developed a communication curriculum with limited didactics and emphasis on practice. Our objective was to evaluate whether this time-limited intervention led to changes in surgical resident communication skills. DESIGN: A 4-module curriculum was implemented for surgical residents (PGY2-4). Each 30-minute module focused on specific communication micro-skills: empathy, concerns and expectations, chunking information and avoiding jargon, and teach-back. Modules included brief didactics, simulated patient interactions, feedback, and debriefing. Precurriculum, residents completed a 2-station objective structured clinical examination (OSCE) and a survey on communication confidence. Residents evaluated each module and postcurriculum, completed another 2-station OSCE, confidence survey, and overall curriculum evaluation. Using validated rating scales, OSCEs were scored by 2 independent raters. SETTING: Tertiary care, academic center with a 5-year surgical residency program. PARTICIPANTS: All 17 eligible residents completed both OSCEs and surveys, and 14 attended ≥3 modules. RESULTS: Following the curriculum, residents reported increased use of the targeted skills and increased confidence in responding to emotions, information sharing, and bad news telling (p < 0.004). There was no change in history taking. Residents rated the usefulness of each module modestly (2.5-3.1, scale 0-4), however, the likelihood of skill implementation was higher (3.2-3.6). The overall postcurriculum OSCE scores increased (versus precurriculum scores, p < 0.001). Postcurriculum scores increased for empathy, concerns and expectations, and teach-back. Chunking information and avoiding jargon was unchanged. Fifteen residents reported module length as appropriate, and 2 thought they were too short. CONCLUSIONS: The brief modules led to increased self-reported use of communication skills and were effective in improving resident communication in OSCEs. This may be a useful curricular model for both surgical and nonsurgical residency programs with limited availability for curricular time.

A TFAP2C Gene Signature Is Predictive of Outcome in HER2-Positive Breast Cancer.

The AP-2γ transcription factor, encoded by the TFAP2C gene, regulates the expression of estrogen receptor-alpha (ERα) and other genes associated with hormone response in luminal breast cancer. Little is known about the role of AP-2γ in other breast cancer subtypes. A subset of HER2+ breast cancers with amplification of the TFAP2C gene locus becomes addicted to AP-2γ. Herein, we sought to define AP-2γ gene targets in HER2+ breast cancer and identify genes accounting for physiologic effects of growth and invasiveness regulated by AP-2γ. Comparing HER2+ cell lines that demonstrated differential response to growth and invasiveness with knockdown of TFAP2C, we identified a set of 68 differentially expressed target genes. CDH5 and CDKN1A were among the genes differentially regulated by AP-2γ and that contributed to growth and invasiveness. Pathway analysis implicated the MAPK13/p38δ and retinoic acid regulatory nodes, which were confirmed to display divergent responses in different HER2+ cancer lines. To confirm the clinical relevance of the genes identified, the AP-2γ gene signature was found to be highly predictive of outcome in patients with HER2+ breast cancer. We conclude that AP-2γ regulates a set of genes in HER2+ breast cancer that drive cancer growth and invasiveness. The AP-2γ gene signature predicts outcome of patients with HER2+ breast cancer and pathway analysis predicts that subsets of patients will respond to drugs that target the MAPK or retinoic acid pathways. IMPLICATIONS: A set of genes regulated by AP-2γ in HER2+ breast cancer that drive proliferation and invasion were identified and provided a gene signature that is predictive of outcome in HER2+ breast cancer.