Distinct genomic landscapes of gastroesophageal adenocarcinoma depending on PD-L1 expression identify mutations in RAS-MAPK pathway and TP53 as potential predictors of immunotherapy efficacy.

BACKGROUND: The impact of molecular alterations on programmed death-ligand 1 (PD-L1) combined positive score (CPS) is not well studied in gastroesophageal adenocarcinomas (GEAs). We aimed to characterize genomic features of tumors with different CPSs in GEAs. PATIENTS AND METHODS: Genomic alterations of 2518 GEAs were compared in three groups (PD-L1 CPS ≥ 10, high; CPS = 1-9, intermediate; CPS < 1, low) using next-generation sequencing. We assessed the impact of gene mutations on the efficacy of immune checkpoint inhibitors (ICIs) and tumor immune environment based on the Memorial Sloan Kettering Cancer Center and The Cancer Genome Atlas databases. RESULTS: High, intermediate, and low CPSs were seen in 18%, 54% and 28% of GEAs, respectively. PD-L1 positivity was less prevalent in women and in tissues derived from metastatic sites. PD-L1 CPS was positively associated with mismatch repair deficiency/microsatellite instability-high, but independent of tumor mutation burden distribution. Tumors with mutations in KRAS, TP53, and RAS-mitogen-activated protein kinase (MAPK) pathway were associated with higher PD-L1 CPSs in the mismatch repair proficiency and microsatellite stability (pMMR&MSS) subgroup. Patients with RAS-MAPK pathway alterations had longer overall survival (OS) from ICIs compared to wildtype (WT) patients [27 versus 13 months, hazard ratio (HR) = 0.36, 95% confidence interval (CI): 0.19-0.7, P = 0.016] and a similar trend was observed in the MSS subgroup (P = 0.11). In contrast, patients with TP53 mutations had worse OS from ICIs compared to TP53-WT patients in the MSS subgroup (5 versus 21 months, HR = 2.39, 95% CI: 1.24-4.61, P = 0.016). CONCLUSIONS: This is the largest study to investigate the distinct genomic landscapes of GEAs with different PD-L1 CPSs. Our data may provide novel insights for patient selection using mutations in TP53 and RAS-MAPK pathway and for the development of rational combination immunotherapies in GEAs.

Assessment of immune biomarkers and establishing a triple negative phenotype in gynecologic cancers.

OBJECTIVE: Immuno-oncology (IO) has rapidly evolved, with many IO therapies either approved or under investigation for multiple malignancies. Biomarkers exist that can predict response to IO therapies including PD-L1 expression, microsatellite instability (MSI), and total mutation burden (TMB). This paper serves to analyze the presence of these biomarkers across gynecologic cancers. METHODS: A total of 16,300 gynecologic cancer specimens submitted for molecular profiling to Caris Life Sciences were reviewed. Immunohistochemistry was performed using the SP142 anti-PD-L1 clone and assessed for intensity. Next-generation sequencing, immunohistochemistry, and fragment analysis were used to determine MSI status. TMB was measured by counting all non-synonymous missense mutations found per tumor not previously described as germline alterations. Chi-Square, Fisher Exact, and the Kruskal-Wallis test were used to compare cohorts. RESULTS: Of 16,300 specimens, 54.1% were ovarian, 37.2% uterine, 7.2% cervical, 0.3% vulvar, 1.2% vaginal, with 0.1% unspecified. MSI-H was most frequent in uterine cancer (17.7%) and only 1% of ovarian cancers. PD-L1 expression was present in 38.3% of cervical and 62.5% of vulvar cancers, but less than 8% of ovarian and uterine cancers. TMB-H was present in 21.1% cervical, 19.7% uterine, and 5% ovarian cancers. Few specimens exhibited a "triple positive" phenotype - 0.3% ovarian, 1.5% uterine, and 1.5% cervical. Associations were seen between MSI, TMB, and PD-L1 across all cancer types. CONCLUSIONS: The frequency of individual biomarkers pertinent to IO therapy varies by cancer type. HPV-driven genital tract cancers have higher frequencies of PD-L1 expression, MSI-H, and TMBH. Endometrial cancers are characterized by MSI-H and TMB, whereas ovarian cancers have a low frequency of MSI-H and modest PD-L1 or TMBH. The incidence of 'triple positive" cases was less than 2%.

A phase 1 trial of imatinib, bevacizumab, and metronomic cyclophosphamide in advanced colorectal cancer.

BACKGROUND: This phase 1 clinical trial was conducted to determine the safety, maximum-tolerated dose (MTD), and pharmacokinetics of imatinib, bevacizumab, and metronomic cyclophosphamide in patients with advanced colorectal cancer (CRC). METHODS: Patients with refractory stage IV CRC were treated with bevacizumab 5 mg kg(-1) i.v. every 2 weeks (fixed dose) plus oral cyclophosphamide q.d. and imatinib q.d. or b.i.d. in 28-day cycles with 3+3 dose escalation. Response was assessed every two cycles. Pharmacokinetics of imatinib and cyclophosphamide and circulating tumour, endothelial, and immune cell subsets were measured. RESULTS: Thirty-five patients were enrolled. Maximum-tolerated doses were cyclophosphamide 50 mg q.d., imatinib 400 mg q.d., and bevacizumab 5 mg kg(-1) i.v. every 2 weeks. Dose-limiting toxicities (DLTs) included nausea/vomiting, neutropaenia, hyponatraemia, fistula, and haematuria. The DLT window required expansion to 42 days (1.5 cycles) to capture delayed toxicities. Imatinib exposure increased insignificantly after adding cyclophosphamide. Seven patients (20%) experienced stable disease for >6 months. Circulating tumour, endothelial, or immune cells were not associated with progression-free survival. CONCLUSION: The combination of metronomic cyclophosphamide, imatinib, and bevacizumab is safe and tolerable without significant drug interactions. A subset of patients experienced prolonged stable disease independent of dose level.

Temsirolimus combined with sorafenib in hepatocellular carcinoma: a phase I dose-finding trial with pharmacokinetic and biomarker correlates.

BACKGROUND: Based upon preclinical evidence for improved antitumor activity in combination, this phase I study investigated the maximum-tolerated dose (MTD), safety, activity, pharmacokinetics (PK), and biomarkers of the mammalian target of rapamycin inhibitor, temsirolimus, combined with sorafenib in hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Patients with incurable HCC and Child Pugh score ≤B7 were treated with sorafenib plus temsirolimus by 3 + 3 design. The dose-limiting toxicity (DLT) interval was 28 days. The response was assessed every two cycles. PK of temsirolimus was measured in a cohort at MTD. RESULTS: Twenty-five patients were enrolled. The MTD was temsirolimus 10 mg weekly plus sorafenib 200 mg twice daily. Among 18 patients at MTD, DLT included grade 3 hand-foot skin reaction (HFSR) and grade 3 thrombocytopenia. Grade 3 or 4 related adverse events at MTD included hypophosphatemia (33%), infection (22%), thrombocytopenia (17%), HFSR (11%), and fatigue (11%). With sorafenib, temsirolimus clearance was more rapid (P < 0.05). Two patients (8%) had a confirmed partial response (PR); 15 (60%) had stable disease (SD). Alpha-fetoprotein (AFP) declined ≥50% in 60% assessable patients. CONCLUSION: The MTD of sorafenib plus temsirolimus in HCC was lower than in other tumor types. HCC-specific phase I studies are necessary. The observed efficacy warrants further study.

Loss of p14ARF in tumor cells facilitates replication of the adenovirus mutant dl1520 (ONYX-015).

The adenovirus mutant dl1520 (ONYX-015) does not express the E1B-55K protein that binds and inactivates p53. This virus replicates in tumor cells with mutant p53, but not in normal cells with functional p53. Although intra-tumoral injection of dl1520 shows promising responses in patients with solid tumors, previous in vitro studies have not established a close correlation between p53 status and dl1520 replication. Here we identify loss of p14ARF as a mechanism that allows dl1520 replication in tumor cells retaining wild-type p53. We demonstrate that the re-introduction of p14ARF into tumor cells with wild-type p53 suppresses replication of dl1520 in a p53-dependent manner. Our study supports the therapeutic use of dl1520 in tumors with lesions within the p53 pathway other than mutation of p53.

Minimal hepatic toxicity of Onyx-015: spatial restriction of coxsackie-adenoviral receptor in normal liver.

We administered an adenoviral vector, Onyx-015, into the hepatic artery of patients with metastatic colorectal cancer involving the liver. Thirty-five patients enrolled in this multi-institutional phase I/II trial received up to eight arterial infusions of up to 2 x 10(12) viral particles. Hepatic toxicity was the primary dose-limiting toxicity observed in preclinical models. However, nearly 200 infusions of this adenoviral vector were administered directly into the hepatic artery without significant toxicity. Therefore, we undertook this analysis to determine the impact of repeated adenoviral exposure on hepatic function. Seventeen patients were treated at our institution, providing a detailed data set on the changes in hepatic function following repeated exposure to adenovirus. No changes in hepatic function occurred with the first treatment of Onyx-015 among these patients. Transient increases in transaminase levels occurred in one patient starting with the second infusion and transient increases in bilirubin was observed in two patients starting with the fifth treatment. These changes occurred too early to be explained by viral-mediated lysis of hepatocytes. In addition, viremia was observed starting 3-5 days after the viral infusion in half of the patient, but was not associated with hepatic toxicity. To further understand the basis for the minimal hepatic toxicity of adenoviral vectors, we evaluated the replication of adenovirus in primary hepatocytes and tumor cells in culture and the expression of the coxsackie-adenoviral receptor (CAR) in normal liver and colon cancer metastatic to the liver. We found that adenovirus replicates poorly in primary hepatocytes but replicates efficiently in tumors including tumors derived from hepatocytes. In addition, we found that CAR is localized at junctions between hepatocytes and is inaccessible to hepatic blood flow. CAR is not expressed on tumor vasculature but is expressed on tumor cells. Spatial restriction of CAR to the intercellular space in normal liver and diminished replication of adenovirus in hepatocytes may explain the minimal toxicity observed following repeated hepatic artery infusions with Onyx-015.

Expression of the coxsackievirus- and adenovirus receptor in gastrointestinal cancer correlates with tumor differentiation.

Modified adenoviruses represent a new approach to treatment of gastrointestinal cancer. However, their uptake by cells in many cases requires the major receptor for adenoviruses, the coxsackievirus and adenovirus receptor (CAR). Thus, lack of CAR expression is a potential cause of intrinsic resistance of tumor cells to this type of treatment. To evaluate this, we studied the localization of CAR protein in normal and malignant gastrointestinal tissues. In normal tissues, CAR was concentrated at sites of cell-cell interaction, in particular at the apico-lateral cellular surface. Expression was particularly strong around bile and pancreatic ducts, which is in agreement with CAR's physiological function as a tight-junction protein. In GI malignancies (esophageal, pancreatic, colorectal and liver cancer), expression of the receptor varied substantially. Loss of CAR expression at cell-cell junction was evident in many samples. A significant correlation between CAR expression and histological grade was found, with moderately to poorly differentiated tumors most frequently demonstrating loss or reduction of CAR expression. These data indicate that CAR expression is frequently altered in gastrointestinal malignancy, potentially reducing the efficacy of adenovirus-based therapies.

Use of fluorescence in situ hybridization and comparative genomic hybridization in the cytogenetic analysis of testicular germ cell tumors and uveal melanomas.

Fluorescence in situ hybridization (FISH) with specific DNA probes and comparative genomic hybridization (CGH) are molecular cytogenetic methods that provide powerful supplementations of classical cancer cytogenetics. We present two examples of successful application of these new techniques in solid tumors in which basic information about specific cytogenetic aberrations had been gained previously by conventional karyotyping. In the first, testicular germ cell tumors (TGCT), FISH analysis allowed further characterization of the i(12p) marker chromosome. By CGH, chromosomal subregions that may harbor genes important for tumorigenesis or progression could be identified. In the second, uveal melanoma, CGH enabled a retrospective study in which monosomy 3 was statistically proved to be a relevant marker for poor prognosis.

RNA interference-mediated knockdown of p21(WAF1) enhances anti-tumor cell activity of oncolytic adenoviruses.

The ability of oncolytic adenoviruses to replicate in and lyse cancer cells offers a potential therapeutic approach. However, selectivity and efficacy of adenovirus replication need to be improved. In this study, we present that loss of p21(WAF1) promotes adenovirus replication and more effective cell killing. To test our hypothesis, we took HCT116 colon cancer cell lines carrying deletions of either p21(WAF1) or p53, and infected these cell lines with wild-type adenovirus (WtD) or the oncolytic adenoviruses, ONYX-015 and Delta-24. We found that WtD, ONYX-015 and Delta-24 induced stronger cytopathic effects in HCT116 p21-/- cells compared with HCT116-WT cells. This was accompanied by increased virus production. siRNA-mediated knockdown of p21(WAF1), and similarly of p27(KIP1), in HCT116-WT cells also enhanced replication of and cell killing by these viruses. Furthermore, we found that TE7, an esophageal carcinoma cell line, also showed a strong cell-killing effect and virus production when p21(WAF1) expression was suppressed by RNA interference before adenoviruses infection. Also, H1299 and DU-145 cells transfected with p21(WAF1) siRNA showed higher virus production after ONYX-015 and Delta-24 infections. These observations suggest that p21(WAF1) plays a role in mediating replication of oncolytic viruses with potential implications for adenoviral therapy of cancer.

ONYX-015: mechanisms of action and clinical potential of a replication-selective adenovirus.

Accumulated knowledge in the molecular processes of tumour development combined with the availability of genetically modified viruses resemble the basis for new promising cancer therapeutics. The main advantages of employing replication-competent viruses are achievement of tumour selective killing and amplification of their oncolytic potential within the tumour mass. In this review, we describe the development of ONYX-015, one of the first and most advanced replication-competent viruses for cancer therapy. We discuss the molecular biology of this therapeutic approach and the interesting results obtained with this virus in clinical trials.

Chromosome arm 20q gains and other genomic alterations in colorectal cancer metastatic to liver, as analyzed by comparative genomic hybridization and fluorescence in situ hybridization.

Comprehensive information about the molecular cytogenetic changes in metastases of colorectal cancer is not yet available. To define such changes in metastases, we measured relative DNA sequence copy numbers by comparative genomic hybridization (CGH). Samples from 27 liver metastases and 6 synchronous primary tumors were analyzed. An average of 9.9 aberrations per tumor was found in the metastases. Gains of chromosome arms 20q (85%), 13q (48%), 7p (44%), and 8q (44%) and losses of chromosome arms 18q (89%), 8p (59%), 1p (56%), and 18p (48%) were detected most frequently. Chromosomes 14 and 15 were lost in 26% and 30% of the metastases, respectively. No consistent differences were observed between primary tumors and synchronous metastases. Fluorescence in situ hybridization (FISH) was used for further characterization of gains of chromosome arm 20q. Touch preparations of 13 tumors that had demonstrated 20q gain with CGH were examined with FISH by use of a set of probes mapping to different parts of 20q. A probe for 20p was used as a reference. FISH showed relative gain of at least one 20q locus in 12 of the tumors. High-level gains were detected in 38% of the tumors, preferentially for probes mapping to band 20q13. Our CGH data indicate that colorectal metastases show chromosomal changes similar to those that have been reported for primary tumors. Chromosomal losses were seen at higher frequency, particularly for chromosomes 14 and 15. By FISH, we identified subregions on chromosome arm 20q that are frequently involved in DNA amplifications in colorectal cancer and that may harbor candidate proto-oncogenes.

Detection of chromosomal DNA gains and losses in testicular germ cell tumors by comparative genomic hybridization.

To extend the results of conventional cytogenetic analysis of testicular germ cell tumors (TGCTs), we applied the new molecular cytogenetic method of comparative genomic hybridization (CGH), which enables the detection of chromosomal imbalances without the need for dividing cells. DNA from II TGCTs was studied by CGH. In all tumors examined, gain of 12p, mostly of the whole p arm, could be demonstrated. However, in three tumors, an amplification of 12p material restricted to the chromosomal bands 12p11.2-p12.1 was found. Further fluorescence in situ hybridization (FISH) analysis using a yeast artificial chromosome (YAC) that was previously mapped to that region revealed multiple copies of that chromosomal segment in interphase nuclei of these tumors. This finding is an important clue to the localization of candidate protooncogenes at 12p involved in TGCTs. Gains of small chromosomal regions at 2p, 4q, 6p, and 19p were also detected recurrently. Furthermore, gains of chromosomes 8, 14, 21, and X as well as loss of chromosome 13 were frequent findings. In conclusion, CGH provides new insights into genetic alterations of TGCTs. By using CGH, chromosomal subregions could be identified that may harbor genes involved in the pathogenesis of this malignancy.