Lindsay Alpert

Genomic Heterogeneity as a Barrier to Precision Medicine in Gastroesophageal Adenocarcinoma

Gastroesophageal adenocarcinoma (GEA) is a lethal disease where targeted therapies, even when guided by genomic biomarkers, have had limited efficacy. A potential reason for the failure of such therapies is that genomic profiling results could commonly differ between the primary and metastatic tumors. To evaluate genomic heterogeneity, we sequenced paired primary GEA and synchronous metastatic lesions across multiple cohorts, finding extensive differences in genomic alterations, including discrepancies in potentially clinically relevant alterations. Multiregion sequencing showed significant discrepancy within the primary tumor (PT) and between the PT and disseminated disease, with oncogene amplification profiles commonly discordant. In addition, a pilot analysis of cell-free DNA (cfDNA) sequencing demonstrated the feasibility of detecting genomic amplifications not detected in PT sampling. Lastly, we profiled paired primary tumors, metastatic tumors, and cfDNA from patients enrolled in the personalized antibodies for GEA (PANGEA) trial of targeted therapies in GEA and found that genomic biomarkers were recurrently discrepant between the PT and untreated metastases. Divergent primary and metastatic tissue profiling led to treatment reassignment in 32% (9/28) of patients. In discordant primary and metastatic lesions, we found 87.5% concordance for targetable alterations in metastatic tissue and cfDNA, suggesting the potential for cfDNA profiling to enhance selection of therapy.Significance: We demonstrate frequent baseline heterogeneity in targetable genomic alterations in GEA, indicating that current tissue sampling practices for biomarker testing do not effectively guide precision medicine in this disease and that routine profiling of metastatic lesions and/or cfDNA should be systematically evaluated. Cancer Discov; 8(1); 37-48. ©2017 AACR.See related commentary by Sundar and Tan, p. 14See related article by Janjigian et al., p. 49This article is highlighted in the In This Issue feature, p. 1.

Targeted Therapies for Targeted Populations: Anti-EGFR Treatment for EGFR-Amplified Gastroesophageal Adenocarcinoma

Previous anti-EGFR trials in unselected patients with gastroesophageal adenocarcinoma (GEA) were resoundingly negative. We identified EGFR amplification in 5% (19/363) of patients at the University of Chicago, including 6% (8/140) who were prospectively screened with intention-to-treat using anti-EGFR therapy. Seven patients received ≥1 dose of treatment: three first-line FOLFOX plus ABT-806, one second-line FOLFIRI plus cetuximab, and three third/fourth-line cetuximab alone. Treatment achieved objective response in 58% (4/7) and disease control in 100% (7/7) with a median progression-free survival of 10 months. Pretreatment and posttreatment tumor next-generation sequencing (NGS), serial plasma circulating tumor DNA (ctDNA) NGS, and tumor IHC/FISH for EGFR revealed preexisting and/or acquired genomic events, including EGFR-negative clones, PTEN deletion, KRAS amplification/mutation, NRAS, MYC, and HER2 amplification, and GNAS mutations serving as mechanisms of resistance. Two evaluable patients demonstrated interval increase of CD3+ infiltrate, including one who demonstrated increased NKp46+, and PD-L1 IHC expression from baseline, suggesting an immune therapeutic mechanism of action. EGFR amplification predicted benefit from anti-EGFR therapy, albeit until various resistance mechanisms emerged.Significance: This paper highlights the role of EGFR inhibitors in EGFR-amplified GEA-despite negative results in prior unselected phase III trials. Using serial ctDNA and tissue NGS, we identified mechanisms of primary and acquired resistance in all patients, as well as potential contribution of antibody-dependent cell-mediated cytotoxicity to their clinical benefit. Cancer Discov; 8(6); 696-713. ©2018 AACR.See related commentary by Strickler, p. 679This article is highlighted in the In This Issue feature, p. 663.

Activation of the Renin-Angiotensin System Promotes Colitis Development

The renin-angiotensin system (RAS) plays pathogenic roles in renal and cardiovascular disorders, but whether it is involved in colitis is unclear. Here we show that RenTgMK mice that overexpress active renin from the liver developed more severe colitis than wild-type controls. More than 50% RenTgMK mice died whereas all wild-type mice recovered. RenTgMK mice exhibited more robust mucosal TH17 and TH1/TH17 responses and more profound colonic epithelial cell apoptosis compared to wild-type controls. Treatment with aliskiren (a renin inhibitor), but not hydralazine (a smooth muscle relaxant), ameliorated colitis in RenTgMK mice, although both drugs normalized blood pressure. Chronic infusion of angiotensin II into wild-type mice mimicked the severe colitic phenotype of RenTgMK mice, and treatment with losartan [an angiotensin type 1 receptor blocker (ARB)] ameliorated colitis in wild-type mice, confirming a colitogenic role for the endogenous RAS. In human biopsies, pro-inflammatory cytokines were suppressed in patients with inflammatory bowel disease who were on ARB therapy compared to patients not receiving ARB therapy. These observations demonstrate that activation of the RAS promotes colitis in a blood pressure independent manner. Angiotensin II appears to drive colonic mucosal inflammation by promoting intestinal epithelial cell apoptosis and mucosal TH17 responses in colitis development.

Colorectal Carcinomas With Isolated Loss of PMS2 Staining by Immunohistochemistry

CONTEXT - Isolated loss of PMS2 staining is an uncommon immunophenotype in colorectal carcinomas, accounting for approximately 4% of tumors with microsatellite instability. Limited information regarding these tumors is available in the literature. OBJECTIVE - To compare the clinicopathologic features of colorectal carcinomas with isolated PMS2 loss by immunohistochemistry to those with other forms of mismatch repair deficiency. DESIGN - Ninety-three colorectal carcinomas with isolated PMS2 loss by immunohistochemistry and 193 with other forms of mismatch repair deficiency were identified. Forty (43%) of the isolated PMS2 loss cases and 35 control cases (18%) had a known germline mutation or a clinical diagnosis of Lynch syndrome. RESULTS - Overall, isolated PMS2-loss tumors occurred in significantly younger patients ( P < .001) and in fewer female patients ( P = .006). These tumors were significantly less likely to be right-sided ( P = .001), high-grade ( P = .01), or display histologic features of microsatellite instability ( P < .001). The isolated PMS2-loss group also exhibited increased odds of disease-specific death (odds ratio [OR], 3.09; 95% CI, 1.41-6.85; P = .007). When the analysis was restricted to germline mutation/Lynch syndrome cases and controls, no significant differences were detected for age, sex, tumor location, tumor grade, histologic features, or distant metastases, although a trend toward increased odds of disease-specific death in the isolated PMS2-loss group was evident (OR, 3.87; 95% CI, 0.89-27.04; P = .10). CONCLUSIONS - Unusual clinicopathologic features observed in colorectal carcinomas with isolated PMS2 loss are likely related to the high proportion of cases caused by germline mutations. Isolated PMS2-loss tumors may demonstrate more aggressive behavior than other tumors with microsatellite instability, but larger studies are needed to investigate that possibility further.

Massive Hepatic Infarction Caused by HELLP Syndrome

A healthy, 30-year-old woman at 32 weeks gestation presented to the emergency department with sudden-onset headache and abdominal pain. On physical exam, she was hypertensive (188/69 mm Hg) and had mild tenderness to palpation in the right upper quadrant. Initial laboratory studies revealed proteinuria, aspartate aminotransferase at 730 U/L, and alanine aminotransferase at 478 U/L. She was diagnosed with severe preeclampsia, and an emergent cesarean section was performed.

Treatment outcomes and HPV characteristics for an institutional cohort of patients with anal cancer receiving concurrent chemotherapy and intensity-modulated radiation therapy

Background Intensity-modulated radiation therapy (IMRT) has been used to limit treatment-related toxicity for patients with anal squamous cell carcinoma (SCC). The treatment outcomes and HPV characteristics for a cohort of patients receiving definitive concurrent chemotherapy and IMRT are reported. Materials and methods 52 patients with anal SCC were treated with IMRT and concurrent chemotherapy. Radiation was delivered sequentially to the pelvis and inguinal lymph nodes (45 Gy) and anal tumor (median dose, 54 Gy). Multiplex real-time PCR for 7 high-risk HPV subtypes (n = 22) and p16 immunohistochemistry (n = 21, rated on a 0, 1, and 2+ scale) were performed on available specimens. Survival was estimated using Kaplan-Meier analysis, and toxicities were recorded. Results Median follow-up was 33 months. Three-year freedom from locoregional failure (FFLRF), freedom from distant metastasis (FFDM), freedom from colostomy (FFC), and overall survival (OS) were 94%, 85%, 91%, and 90%, respectively. Acute grade 2+ skin, GI, and GU toxicities occurred in 83%, 71%, and 19% of evaluable patients, respectively. The rates of late grade 2+ GI and GU toxicities for evaluable patients (n = 32) were 28% and 9%, respectively. Of patients with available pathology, 91% and 71% were positive for HPV and p16 (2+), respectively. HPV genotypes included 16 (n = 17), 33 (n = 2), 18 (n = 1), and 45 (n = 1). HPV and p16 status were associated on Chi-square analysis (p = 0.07). Neither HPV nor p16 status was significantly associated with any clinical outcome. For HPV+ patients, 3-year FFLRF, FFDM, FFC, and OS were 100%, 69%, 100%, and 88%, respectively. Conclusions In this patient cohort, disease control was excellent for anal SCC treated with definitive concurrent chemotherapy and IMRT, and treatment was well tolerated. HPV and p16 status were not prognostic for treatment outcomes which may be related to our small sample size.

Lymphocytic colitis: pathologic predictors of response to therapy

Although the presence of intraepithelial lymphocytosis with surface epithelial damage is a unifying feature of lymphocytic colitis, there are nonclassical features that create morphologic heterogeneity between cases. Limited data on the significance of these secondary histologic features are available. Cases of lymphocytic colitis diagnosed between 2002 and 2013 were identified using the Research Patient Data Registry of a tertiary referral center. Diagnostic biopsy slides were reviewed and evaluated for histologic features of lymphocytic colitis. Clinical data including type of therapy and response to treatment were collected. χ2 Test (or Fisher exact test) and logistic regression analysis were used where appropriate. Thirty-two cases of lymphocytic colitis with complete clinical data and slides available for review were identified. The mean age was 56.4 years, and the female-to-male ratio was 3:2. Eleven patients improved with minimal intervention (group 1), 14 patients responded to steroid therapy (group 2), and 7 patients responded to mesalamine, bismuth subsalicylate, and/or cholestyramine therapy (group 3). Histologic differences in the characteristics of the subepithelial collagen table (P = .018), the severity of lamina propria inflammation (P = .042), and the presence of eosinophil clusters (P = .016) were seen between groups 2 and 3. Patients in group 1 were more likely to have mild crypt architectural distortion in their biopsies than patients in groups 2 and 3. Lymphocytic colitis is a heterogeneous disease, and the evaluation of histologic factors may help identify various subtypes and predict therapy response.

Lipomatous Hypertrophy of the Interatrial Septum

A 71-year-old male smoker with a history of diabetes mellitus, hypertension, and prostate cancer status post radiation therapy presented with 2 weeks of progressive dyspnea on exertion. A chest computed tomography scan revealed bilateral ground glass and reticular opacities with focal honeycombing, and pulmonary function testing showed a restrictive pattern of lung disease. Extensive rheumatologic and infectious workups were unrevealing. The patient’s hospital course was notable for the development of atrial fibrillation with a rapid ventricular rate as well as a rapid decline in respiratory status. He died less than a month after his initial presentation. A limited autopsy of the heart and lungs was performed. Examination of the lungs revealed usual interstitial pneumonia with superimposed organizing diffuse alveolar damage, consistent with an acute exacerbation of idiopathic pulmonary fibrosis. The patient’s heart showed evidence of hypertensive and ischemic heart disease. Additionally, a 2.5-cm well-circumscribed area of nodular thickening was identified in the interatrial septum. On cut section, the area of thickening consisted of yellow, lobulated soft tissue (Figure 1A). Histologic examination revealed mature adipose tissue with interspersed bundles of hypertrophied cardiac myocytes showing prominent variation in nuclear size and shape (Figure 1B and C). The findings are consistent with lipomatous hypertrophy of the interatrial septum. 708398 IJSXXX10.1177/1066896917708398International Journal of Surgical PathologyAlpert and Antic research-article2017

Altered Bowel Movements: A Rare Rectal Lesion

DIS 5.4.0 DTD YGAST60275 proof 24 March 2016 5:18 am ce Gas 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Question: A 45-yearold man with a remote history of testicular cancer status post chemoradiation therapy, which was completed 20 years before this presentation and currently in clinical remission, was referred to our institution for intermittent rectal bleeding and diarrhea. He denied weight loss and never 86 87 88 89 90 91 92 93 94 underwent colonoscopy. No palpable lymphadenopathy or abdominal masses were appreciated on physical examination. Colonoscopy showed a 3-cm mass lesion at 10 cm from the anal verge. The lesion had a central umbilication with raised edges, and no obvious ulceration was seen (Figure A). Endoscopic ultrasonography revealed a hypoechoic mass with central depression and the endosonographic borders were smooth. There was sonographic evidence suggesting that the mass remained confined to the mucosa (layers 1 and 2) without extension into the submucosa despite the centrally depressed region (Figure B, arrows). No lymph nodes were seen in the perirectal region. Correlating his clinical and endoscopic findings, what is the diagnosis? Look on page 000 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. 95 96 97 98 99 100 101 Conflicts of interest The authors disclose no conflicts.