Summary Population-based differences in toxicity and clinical outcome following treatment with anticancer drugs have an important effect on oncology practice and drug development. These differences ...arise from complex interactions between biological and environmental factors, which include genetic diversity affecting drug metabolism and the expression of drug targets, variations in tumour biology and host physiology, socioeconomic disparities, and regional preferences in treatment standards. Some well-known examples include the high prevalence of activating epidermal growth factor receptor ( EGFR ) mutations in pulmonary adenocarcinoma among northeast (China, Japan, Korea) and parts of southeast Asia (excluding India) non-smokers, which predict sensitivity to EGFR kinase inhibitors, and the sharp contrast between Japan and the west in the management and survival outcome of gastric cancer. This review is a critical overview of population-based differences in the four most prevalent cancers in the world: lung, breast, colorectal, and stomach cancer. Particular attention is given to the clinical relevance of such knowledge in terms of the individualisation of drug therapy and in the design of clinical trials.
In this issue of Cancer Cell, Yang et al. report the third in a series of phase III trials that demonstrates the survival benefit of combining a PD-1 inhibitor with chemotherapy in nasopharyngeal ...cancer. A gene expression analysis identifies “hot” and “cold” tumor signatures with prognostic and predictive significance.
In this issue of Cancer Cell, Yang et al. report the third in a series of phase III trials that demonstrates the survival benefit of combining a PD-1 inhibitor with chemotherapy in nasopharyngeal cancer. A gene expression analysis identifies “hot” and “cold” tumor signatures with prognostic and predictive significance.
We explored the detection of genome-wide hypomethylation in plasma using shotgun massively parallel bisulfite sequencing as a marker for cancer. Tumor-associated copy number aberrations (CNAs) could ...also be observed from the bisulfite DNA sequencing data. Hypomethylation and CNAs were detected in the plasma DNA of patients with hepatocellular carcinoma, breast cancer, lung cancer, nasopharyngeal cancer, smooth muscle sarcoma, and neuroendocrine tumor. For the detection of nonmetastatic cancer cases, plasma hypomethylation gave a sensitivity and specificity of 74% and 94%, respectively, when a mean of 93 million reads per case were obtained. Reducing the sequencing depth to 10 million reads per case was found to have no adverse effect on the sensitivity and specificity for cancer detection, giving respective figures of 68% and 94%. This characteristic thus indicates that analysis of plasma hypomethylation by this sequencing-based method may be a relatively cost-effective approach for cancer detection. We also demonstrated that plasma hypomethylation had utility for monitoring hepatocellular carcinoma patients following tumor resection and for detecting residual disease. Plasma hypomethylation can be combined with plasma CNA analysis for further enhancement of the detection sensitivity or specificity using different diagnostic algorithms. Using the detection of at least one type of aberration to define an abnormality, a sensitivity of 87% could be achieved with a specificity of 88%. These developments have thus expanded the applications of plasma DNA analysis for cancer detection and monitoring.
Epstein-Barr virus (EBV) is associated with a number of diseases, including malignancies. Currently, it is not known whether patients with different EBV-associated diseases have different methylation ...profiles of circulating EBV DNA. Through whole-genome methylation analysis of plasma samples from patients with nasopharyngeal carcinoma (NPC), EBV-associated lymphoma and infectious mononucleosis, we demonstrate that EBV DNA methylation profiles exhibit a disease-associated pattern. This observation implies a significant potential for the development of methylation analysis of plasma EBV DNA for NPC diagnostics. We further analyse the plasma EBV DNA methylome of NPC and non-NPC subjects from a prospective screening cohort. Plasma EBV DNA fragments demonstrate differential methylation patterns between NPC and non-NPC subjects. Combining such differential methylation patterns with the fractional concentration (count) and size of plasma EBV DNA, population screening of NPC is performed with an improved positive predictive value of 35.1%, compared to a count- and size-based only protocol.
Peptides/small proteins, encoded by noncanonical open reading frames (ORF) of previously claimed non-coding RNAs, have recently been recognized possessing important biological functions, but largely ...uncharacterized. 1p36 is an important tumor suppressor gene (TSG) locus frequently deleted in multiple cancers, with critical TSGs like TP73, PRDM16, and CHD5 already validated. Our CpG methylome analysis identified a silenced 1p36.3 gene KIAA0495, previously thought coding long non-coding RNA. We found that the open reading frame 2 of KIAA0495 is actually protein-coding and translating, encoding a small protein SP0495. KIAA0495 transcript is broadly expressed in multiple normal tissues, but frequently silenced by promoter CpG methylation in multiple tumor cell lines and primary tumors including colorectal, esophageal and breast cancers. Its downregulation/methylation is associated with poor survival of cancer patients. SP0495 induces tumor cell apoptosis, cell cycle arrest, senescence and autophagy, and inhibits tumor cell growth in vitro and in vivo. Mechanistically, SP0495 binds to phosphoinositides (PtdIns(3)P, PtdIns(3,5)P2) as a lipid-binding protein, inhibits AKT phosphorylation and its downstream signaling, and further represses oncogenic AKT/mTOR, NF-κB, and Wnt/β-catenin signaling. SP0495 also regulates the stability of autophagy regulators BECN1 and SQSTM1/p62 through modulating phosphoinositides turnover and autophagic/proteasomal degradation. Thus, we discovered and validated a 1p36.3 small protein SP0495, functioning as a novel tumor suppressor regulating AKT signaling activation and autophagy as a phosphoinositide-binding protein, being frequently inactivated by promoter methylation in multiple tumors as a potential biomarker.
Measurement of DNA derived from different tissues in the circulating DNA pool can provide important information regarding the presence of many pathological conditions. However, existing methods ...involving genome-wide bisulfite sequencing are relatively expensive and may present challenges for large-scale analysis.
Through identifying differentially methylated regions in the liver and colon compared with other tissues, we identified 2 markers and developed corresponding droplet digital PCR assays. Plasma concentrations of liver-derived and colon-derived DNA were measured for 13 liver transplant recipients, 40 liver cancer patients, and 62 colorectal cancer (CRC) patients (27 with and 35 without liver metastases).
In liver transplant recipients, the fractional concentration of liver-derived DNA measured using the liver-specific methylation marker and donor-specific alleles showed good correlation (Pearson
= 0.99). In liver cancer patients, the concentration of liver-derived DNA correlated positively with the maximal dimension of the tumor (Spearman
= 0.74). In CRC patients with and without liver metastasis, the plasma concentrations of colon-derived DNA (median, 138 copies/mL and 4 copies/mL, respectively) were increased compared with the 30 healthy controls (26 had undetectable concentrations). The absolute concentration of liver-derived DNA provided a better differentiation between CRC patients with and without liver metastasis compared with the fractional concentration (area under ROC curve, 0.85 vs 0.75).
Quantitative analysis of plasma DNA with tissue-specific methylation patterns using droplet digital PCR is applicable for the investigation of cancers and assessing organ transplantation. This approach is useful for differentiating patients with and without metastases to other organs.
Abstract
Interplay between EBV infection and acquired genetic alterations during nasopharyngeal carcinoma (NPC) development remains vague. Here we report a comprehensive genomic analysis of 70 NPCs, ...combining whole-genome sequencing (WGS) of microdissected tumor cells with EBV oncogene expression to reveal multiple aspects of cellular-viral co-operation in tumorigenesis. Genomic aberrations along with EBV-encoded LMP1 expression underpin constitutive NF-κB activation in 90% of NPCs. A similar spectrum of somatic aberrations and viral gene expression undermine innate immunity in 79% of cases and adaptive immunity in 47% of cases; mechanisms by which NPC may evade immune surveillance despite its pro-inflammatory phenotype. Additionally, genomic changes impairing
TGFBR2
promote oncogenesis and stabilize EBV infection in tumor cells. Fine-mapping of
CDKN2A/CDKN2B
deletion breakpoints reveals homozygous
MTAP
deletions in 32-34% of NPCs that confer marked sensitivity to MAT2A inhibition. Our work concludes that NPC is a homogeneously NF-κB-driven and immune-protected, yet potentially druggable, cancer.
There are limitations in using radiologic evaluation to assess the treatment outcome of patients with hepatocellular carcinoma (HCC). The use of serial alpha-fetoprotein (AFP) in monitoring response ...has not been rigorously evaluated. We aimed to study the clinical value of AFP trend in an attempt to validate AFP as a surrogate serologic end point.
Participants from a phase III randomized trial of systemic chemotherapy in HCC were studied. Serum AFP was prospectively collected in parallel with clinical and radiologic outcome. AFP response was defined as a decrease in AFP of more than 20% after a minimum of two cycles of chemotherapy. We studied the relationship between AFP response and treatment outcome in terms of radiologic response and overall survival.
Of 188 patients, 117 patients with elevated serum AFP (> 20 microg/L) and documented radiologic evaluation had received at least two cycles of chemotherapy. A total of 47 AFP responders were identified. AFP responders had better survival than nonresponders (13.5 v 5.6 months, respectively; P < .0001), and AFP response was strongly associated with radiologic response (P < .0001). Multivariate analysis suggested that AFP response was significantly associated with survival (hazard ratio, 0.413; 95% CI, 0.273 to 0.626; P < .0001). AFP responses were frequently observed in patients with radiologically stable disease (SD) and tended to identify a subgroup of SD patients with better survival.
Serial AFP measurement is useful in prognostication and monitoring treatment response in HCC patients undergoing systemic chemotherapy. Incorporation of AFP response into the criteria evaluating treatment outcome should be considered in clinical practice and clinical trials of novel agents in HCC.
Objectives
MRI can detect early-stage nasopharyngeal carcinoma (NPC), but the detection is more challenging in early-stage NPCs because they must be distinguished from benign hyperplasia in the ...nasopharynx. This study aimed to determine whether intravoxel incoherent motion diffusion-weighted imaging (IVIM DWI) MRI could distinguish between these two entities.
Methods
Thirty-four subjects with early-stage NPC and 30 subjects with benign hyperplasia prospectively underwent IVIM DWI. The mean pure diffusion coefficient (
D
), pseudo-diffusion coefficient (
D
*), perfusion fraction (
f
) and apparent diffusion coefficient (ADC) values were calculated for all subjects and compared between the 2 groups using Student’s
t
test. Receiver operating characteristics with the area under the curve (AUC) was used to identify the optimal threshold for all significant parameters, and the corresponding diagnostic performance was calculated. A
p
value of < 0.05 was considered statistically significant.
Results
Compared with benign hyperplasia, early-stage NPC exhibited a significantly lower
D
mean (0.64 ± 0.06 vs 0.87 ± 0.11 × 10
−3
mm
2
/s), ADC
0–1000
mean (0.77 ± 0.08 vs 1.00 ± 0.13 × 10
−3
mm
2
/s), ADC
300–1000
(0.63 ± 0.05 vs 0.86 ± 0.10 × 10
−3
mm
2
/s) and a higher
D
* mean (32.66 ± 4.79 vs 21.96 ± 5.21 × 10
−3
mm
2
/s) (all
p
< 0.001). No significant difference in the
f
mean was observed between the two groups (
p
= 0.216). The
D
and ADC
300–1000
mean had the highest AUC of 0.985 and 0.988, respectively, and the D mean of < 0.75 × 10
−3
mm
2
/s yielded the highest sensitivity, specificity and accuracy (100%, 93.3% and 96.9%, respectively) in distinguishing early-stage NPC from benign hyperplasia.
Conclusion
DWI has potential to distinguish early-stage NPC from benign hyperplasia and
D
and ADC
300–1000
mean were the most promising parameters.
Key Points
• Diffusion-weighted imaging has potential to distinguish early-stage nasopharyngeal carcinoma from benign hyperplasia in the nasopharynx.
• The pure diffusion coefficient, pseudo-diffusion coefficient from intravoxel incoherent motion model and apparent diffusion coefficient from conventional diffusion-weighted imaging were significant parameters for distinguishing these two entities in the nasopharynx.
• The pure diffusion coefficient, followed by apparent diffusion coefficient, may be the most promising parameters to be used in screening studies to help detect early-stage nasopharyngeal carcinoma.
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