Ji Yun Lee

Association Between PD-L1 and HPV Status and the Prognostic Value of PD-L1 in Oropharyngeal Squamous Cell Carcinoma

Purpose Oropharyngeal squamous cell carcinoma (OSCC) has been recognized as an immunosuppressive disease. Various mechanisms have been proposed for immune escape, including dysregulation of immune checkpoints such as the PD-1:PD-L1 pathway. We investigated the expression of programmed cell death-ligand 1 (PD-L1) in HPV-negative and HPV-positive OSCC to determine its prevalence and prognostic relevance. Materials and Methods Using immunohistochemistry, 133 cases of OSCC were evaluated for expression of PD-L1. Formalin-fixed paraffin-embedded tumor samples were stained with monoclonal antibody (clone 5H1) to PD-L1. PD-L1 positivity was defined as membrane staining in ≥20% of tumor cells. Correlations between PD-L1 expression and HPV status and survival parameters were analyzed. Results Of the 133 patients, 68% showed PD-L1 expression, and 67% of patients were positive for p16 expression by immunohistochemistry. No significant difference in PD-L1 expression was observed between HPV(-) and HPV(+) tumors (61% vs. 71%, p=0.274). No significant difference in age, gender, smoking history, location of tumor origin, or stage was observed according to PD-L1 status. With a median follow-up period of 44 months, older age (≥65) (p=0.017) and T3-4 stage (p<0.001) were associated with poor overall survival (OS), whereas PD-L1 expression did not affect OS in univariate and multivariate analysis. Conclusion PD-L1 expression was observed in the majority of OSCC patients regardless of HPV status. Further large prospective studies are required to determine the role of PD-L1 expression as a prognostic or predictive biomarker, and clinical studies of immune checkpoint inhibitors in OCSS are warranted regardless of HPV status.

Longitudinal monitoring of EGFR mutations in plasma predicts outcomes of NSCLC patients treated with EGFR TKIs: Korean Lung Cancer Consortium (KLCC-12-02)

We hypothesized that plasma-based EGFR mutation analysis for NSCLC may be feasible for monitoring treatment response to EGFR TKIs and also predict drug resistance. Clinically relevant mutations including exon 19 deletion (ex19del), L858R and T790M were analyzed using droplet digital PCR (ddPCR) in longitudinally collected plasma samples (n = 367) from 81 NSCLC patients treated with EGFR TKI. Of a total 58 baseline cell-free DNA (cfDNA) samples available for ddPCR analysis, 43 (74.1%) had the same mutation in the matched tumors (clinical sensitivity: 70.8% [17/24] for L858R and 76.5% [26/34] for ex19del). The concordance rates of plasma with tissue-based results of EGFR mutations were 87.9% for L858R and 86.2% for ex19del. All 40 patients who were detected EGFR mutations at baseline showed a dramatic decrease of mutant copies (>50%) in plasma during the first two months after treatment. Median progression-free survival (PFS) was 10.1 months for patients with undetectable EGFR v 6.3 months for detectable EGFR mutations in blood after two-month treatment (HR 3.88, 95% CI 1.48-10.19, P = 0.006). We observed emerging resistance with early detection of T790M as a secondary mutation in 14 (28.6%) of 49 patients. Plasma-based EGFR mutation analysis using ddPCR can monitor treatment response to EGFR TKIs and can lead to early detection of EGFR TKIs resistance. Further studies confirming clinical implications of EGFR mutation in plasma are warranted to guide optimal therapeutic strategies upon knowledge of treatment response and resistance.

Mutational profiling of brain metastasis from breast cancer: matched pair analysis of targeted sequencing between brain metastasis and primary breast cancer

Although breast cancer is the second most common cause of brain metastasis with a notable increase of incidence, genes that mediate breast cancer brain metastasis (BCBM) are not fully understood. To study the molecular nature of brain metastasis, we performed gene expression profiling of brain metastasis and matched primary breast cancer (BC). We used the Ion AmpliSeq Cancer Panel v2 covering 2,855 mutations from 50 cancer genes to analyze 18 primary BC and 42 BCBM including 15 matched pairs. The most common BCBM subtypes were triple-negative (42.9%) and basal-like (36.6%). In a total of 42 BCBM samples, 32 (76.2%) harbored at least one mutation (median 1, range 0–7 mutations). Frequently detected somatic mutations included TP53 (59.5%), MLH1 (14.3%), PIK3CA (14.3%), and KIT (7.1%). We compared BCBM with patient-matched primary BC specimens. There were no significant differences in mutation profiles between the two groups. Notably, gene expression in BCBM such as TP53, PIK3CA, KIT, MLH1, and RB1 also seemed to be present in primary breast cancers. The TP53 mutation frequency was higher in BCBM than in primary BC (59.5% vs 38.9%, respectively). In conclusion, we found actionable gene alterations in BCBM that were maintained in primary BC. Further studies with functional testing and a delineation of the role of these genes in specific steps of the metastatic process should lead to a better understanding of the biology of metastasis and its susceptibility to treatment.

Patient-derived cell models as preclinical tools for genome-directed targeted therapy

Background In this study, we established patient-derived tumor cell (PDC) models using tissues collected from patients with metastatic cancer and assessed whether these models could be used as a tool for genome-based cancer treatment. Methods PDCs were isolated and cultured from malignant effusions including ascites and pleural fluid. Pathological examination, immunohistochemical analysis, and genomic profiling were performed to compare the histological and genomic features of primary tumors, PDCs. An exploratory gene expression profiling assay was performed to further characterize PDCs. Results From January 2012 to May 2013, 176 samples from patients with metastatic cancer were collected. PDC models were successfully established in 130 (73.6%) samples. The median time from specimen collection to passage 1 (P1) was 3 weeks (range, 0.5–4 weeks), while that from P1 to P2 was 2.5 weeks (range, 0.5–5 weeks). Sixteen paired samples of genomic alterations were highly concordant between each primary tumor and progeny PDCs, with an average variant allele frequency (VAF) correlation of 0.878. We compared genomic profiles of the primary tumor (P0), P1 cells, P2 cells, and patient-derived xenografts (PDXs) derived from P2 cells and found that three samples (P0, P1, and P2 cells) were highly correlated (0.99–1.00). Moreover, PDXs showed more than 100 variants, with correlations of only 0.6–0.8 for the other samples. Drug responses of PDCs were reflective of the clinical response to targeted agents in selected patient PDC lines. Conclusion(s) Our results provided evidence that our PDC model was a promising model for preclinical experiments and closely resembled the patient tumor genome and clinical response.

The Impact of Concomitant Genomic Alterations on Treatment Outcome for Trastuzumab Therapy in HER2-Positive Gastric Cancer

Clinical benefit from trastuzumab and other anti-human epidermal growth factor receptor-2 (HER2) therapies in patients with HER2-positive gastric cancer (GC) remains limited by primary or acquired resistance. We aimed to investigate the impact of concomitant molecular alterations to HER2 amplification on the clinical outcome of trastuzumab-treated patients. Using immunohistochemistry (IHC), copy number variations (CNVs), and Ion Ampliseq Cancer Panel, we analyzed the status of concomitant alterations in 50 HER2-positive advanced GC patients treated with trastuzumab in combination with other chemotherapeutic agents. The percentage of tumor samples with at least one concomitant alteration was 40% as assessed by IHC, 16% by CNVs, and 64% by Ampliseq sequencing. Median progression-free survival (PFS) was 8.0 months (95% confidence interval, 4.8–11.3). Patients were divided into two subgroups according to PFS values with a cutoff point of 8 months; results show that concomitant genomic alterations do not correlate with trastuzumab response. However, CNVs of CCNE1 significantly correlated (p < 0.05) with a shorter survival time. Our findings indicate that additional alterations implemented for prediction of clinical benefit from HER2-targeting agents in GC remained unclear. Further studies will be needed to elucidate the role of each specific biomarker and to optimize therapeutic approaches.

Gene Expression Profiling of Breast Cancer Brain Metastasis

The biology of breast cancer brain metastasis (BCBM) is poorly understood. We aimed to explore genes that are implicated in the process of brain metastasis of primary breast cancer (BC). NanoString nCounter Analysis covering 252 target genes was used for comparison of gene expression levels between 20 primary BCs that relapsed to brain and 41 BCBM samples. PAM50-based intrinsic subtypes such as HER2-enriched and basal-like were clearly over-represented in BCBM. A panel of 22 genes was found to be significantly differentially expressed between primary BC and BCBM. Five of these genes, CXCL12, MMP2, MMP11, VCAM1, and MME, which have previously been associated with tumor progression, angiogenesis, and metastasis, clearly discriminated between primary BC and BCBM. Notably, the five genes were significantly upregulated in primary BC compared to BCBM. Conversely, SOX2 and OLIG2 genes were upregulated in BCBM. These genes may participate in metastatic colonization but not in primary tumor development. Among patient-matched paired samples (n = 17), a PAM50 molecular subtype conversion was observed in eight cases (47.1%), with a trend toward unfavorable subtypes in patients with the distinct gene expression. Our findings, although not conclusive, reveal differentially expressed genes that might mediate the brain metastasis process.

Hepatitis B reactivation in multiple myeloma patients with resolved hepatitis B undergoing chemotherapy.

Despite increasing reports of hepatitis B virus (HBV) reactivation in multiple myeloma (MM), HBV reactivation in patients with resolved hepatitis B [hepatitis B surface antigen (HBsAg)‐negative/anti‐hepatitis B core antigen antibody (anti‐HBc)‐positive] is still poorly characterized. The aim of this study was to clarify its frequency and risk factors.

A Phase Ib/II Study of Afatinib in Combination with Nimotuzumab in Non-Small Cell Lung Cancer Patients with Acquired Resistance to Gefitinib or Erlotinib

Purpose: In this phase Ib/II study, we aimed to assess the safety and efficacy of afatinib plus nimotuzumab (N) in advanced non–small cell lung cancer (NSCLC) patients with acquired resistance to gefitinib or erlotinib. Experimental Design: In phase Ib stage, patients received afatinib (40 mg or 30 mg once daily) plus nimotuzumab (100 mg or 200 mg once weekly) for 28-day cycles to determine the recommended phase II dose (RPIID). The safety and efficacy of RPIID dose was evaluated in phase II stage. Results: In total, 50 patients were enrolled (13 to phase Ib and 37 to phase II). In the first dose-finding cohort (afatinib 40 mg plus nimotuzumab 100 mg), one patient experienced dose-limiting toxicity (DLT) of grade 3 diarrhea and in the subsequent cohort (afatinib 40 mg plus nimotuzumab 200 mg), two DLTs (grade 3 diarrhea and grade 3 neutropenia) occurred in 2 of 6 patients. Accordingly, RPIID was determined as afatinib 40 mg plus nimotuzumab 100 mg. In 44 patients treated with RPIID, 7 (16%) patients had grade 3 toxicities; skin rash (7%), diarrhea (5%), acne (2%), and fatigue (2%). The overall response rate was 23% and the median duration of response was 4.3 months (range, 0.7–16.2 months). The median progression-free survival and overall survival were 4.0 months [95% confidence interval (CI), 2.3–5.7 months] and 11.7 months (95% CI, 9.4–14.0 months), respectively. Conclusions: Combination treatment of afatinib and nimotuzumab demonstrated an acceptable safety profile and encouraging antitumor activity in advanced NSCLC patients with acquired resistance to gefitinib or erlotinib. Larger phase III trial is warranted to confirm its efficacy and safety. Clin Cancer Res; 22(9); 2139–45. ©2015 AACR.

The BIM Deletion Polymorphism and its Clinical Implication in Patients with EGFR-Mutant Non-Small-Cell Lung Cancer Treated with EGFR Tyrosine Kinase Inhibitors

Introduction: A germline BIM deletion polymorphism has been proposed to predict poor treatment response to certain kinase inhibitors. The purpose of this study was to explore whether the BIM deletion polymorphism predicts treatment efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in Korean patients with EGFR-mutant non–small-cell lung cancer (NSCLC). Methods: Peripheral blood samples from a total of 205 patients with EGFR-mutant NSCLC who were treated with EGFR TKIs between July 2008 and April 2013 were included. The incidence of BIM deletions in these samples was detected by polymerase chain reaction. We compared the clinical outcomes in patients with and without the polymorphism after treatment with EGFR TKIs (gefitinib or erlotinib). Results: The BIM deletion polymorphism was present in 15.6% (32 of 205) of patients. One patient was homozygous for the deletion, and the remaining 31 had heterozygous deletions. The majority of patients were younger than 65 years (74%), female (68%), never smokers (76%), and had stage IV NSCLC (67%). There were no associations between the BIM deletion polymorphism and clinicopathological features including gender, age, smoking status, histology, stage, and number of metastasis sites. Patients with and without the BIM deletion polymorphism had similar objective response rates (91 vs. 84%, p = 0.585). Progression-free survival and overall survival did not differ significantly between patients with and without the BIM deletion polymorphism (median progression-free survival 12 vs. 11 months, p = 0.160; median overall survival 31 vs. 30 months, p = 0.452). Multivariate analysis identified significantly predictive markers for clinical outcomes of EGFR TKIs including Eastern Cooperative Oncology Group performance status 0–1, adenocarcinoma histology, recurrent disease, and EGFR mutation type. The results were validated in an independent cohort of 69 NSCLC patients. Conclusions: It remains to be determined whether the BIM deletion polymorphism provides intrinsic resistance or decreased sensitivity to EGFR TKIs in EGFR-mutant NSCLC patients.

MCT4 as a potential therapeutic target for metastatic gastric cancer with peritoneal carcinomatosis

Monocarboxylate transporters (MCTs) play a major role in up-regulation of glycolysis and adaptation to acidosis. However, the role of MCTs in gastric cancer (GC) is not fully understood. We investigated the potential utilization of a new cancer therapy for GC. We characterized the expression patterns of the MCT isoforms 1, 2, and 4 and investigated the role of MCT in GC through in vitro and in vivo tests using siRNA targeting MCTs. In GC cell lines, MCT1, 2, and 4 were up-regulated with different expression levels; MCT1 and MCT4 were more widely expressed in GC cell lines compared with MCT2. Inhibition of MCTs by siRNA or AR-C155858 reduced cell viability and lactate uptake in GC cell lines. The effect of inhibition of MCTs on tumor growth was also confirmed in xenograft models. Furthermore, MCT inhibition in GC cells increased the sensitivity of cells to radiotherapy or chemotherapy. Compared with normal gastric tissue, no significant alterations of expression levels in tumors were identified for MCT1 and MCT2, whereas a significant increase in MCT4 expression was observed. Most importantly, MCT4 was highly overexpressed in malignant cells of acsites and its silencing resulted in reduced tumor cell proliferation and lactate uptake in malignant ascites. Our study suggests that MCT4 is a clinically relevant target in GC with peritoneal carcinomatosis.