Sensitivity and optimal clinicopathological features for mutation-targeted liquid biopsy in pN0M0 EGFR-mutant lung adenocarcinoma.

PURPOSE: Liquid biopsy for early-stage lung cancer diagnosis is challenging, and optimal candidates' clinicopathological features are unknown. We investigated utility and clinicopathological features of optimal candidates in somatic mutation-targeted liquid biopsy using droplet digital polymerase chain reaction (ddPCR) in pN0M0 EGFR mutation-positive lung adenocarcinoma patients. METHODS: We performed EGFR mutation-targeted ddPCR liquid biopsy in 100 patients with resected pN0M0 invasive lung adenocarcinoma, whose tumor diameter in high-resolution computed tomography (HRCT) was ≤ 5 cm. Peripheral blood-derived serum was collected preoperatively. Two representative EGFR somatic variants (exon 19 [E746-A750 del (2235_2249 del)]; exon 21 (L858R)) were utilized as liquid biopsy targets. Clinicopathological features including radiological appearance, subhistology, and invasive status were compared between ddPCR-positive and ddPCR-negative patients. RESULTS: Among the 100 patients, 98 showed part-solid or pure-solid appearance in HRCT and 2 showed non-solid appearance; 98 were pathological stage IA1-IB. Of the 66 patients with EGFR mutation detection in ddPCR, 12 were significantly positive and 10 (83.3%, 10/12) exhibited pure-solid appearance in HRCT. Clinical invasive tumor ratio was significantly higher in ddPCR-positive than in ddPCR-negative patients (median: 100% vs. 85.4%, P = 0.0212), whereas other clinicopathological features were not significantly different. CONCLUSION: Mutation-targeted liquid biopsy using ddPCR detected lung cancer in 12.0% (12/100) of pN0M0 EGFR-mutant lung adenocarcinoma patients. In 83.3% of the ddPCR-positive patients, tumors showed pure-solid appearance in HRCT. The detection ratio increased to 21.3% (10/47) among patients with pure-solid appearance tumors. Tumor appearance might be useful for better selection of liquid biopsy candidates.

Intense Expression of EGFR L858R Characterizes the Micropapillary Component and L858R Is Associated with the Risk of Recurrence in pN0M0 Lung Adenocarcinoma with the Micropapillary Component.

BACKGROUND: Lung adenocarcinoma with the micropapillary (MP) component poses a higher risk of recurrence even when the MP component is not predominant. This study explored genetic features associated with highly malignant behavior of lung adenocarcinoma with the MP component. METHODS: The MP and papillary (PaP) components were captured separately in three patients. Comprehensive mRNA expressions of somatic variants were compared between the MP and PaP components of each patient using next-generation sequencing (NGS). The protein expression of the NGS-detected variant was validated by immunohistochemistry. The prognostic impact of the detected variant was evaluated in 288 adenocarcinoma patients with resection of pN0M0. RESULTS: In two cases, NGS suggested higher RNA expression of EGFR L858R in the MP component than in the PaP component (allele frequency, 0.485 vs. 0.155 and 1.000 vs. 0.526, respectively; P < 0.001 for both). Immunohistochemistry validated intense expression of L858R in the MP component of 27 MP-positive (MP+) patients. Among 288 pN0M0 patients, L858R was more frequently harbored in the MP+ patients than in the MP-negative (MP-) patients. The MP+ patients harboring L858R showed significantly worse recurrence-free survival (RFS) than the MP+ patients without L858R (median RFS 38.7 and 55.0 months, respectively; hazard ratio [HR] 3.004; 95% confidence interval [CI] 1.306-9.132; P = 0.012). Multivariate analysis of the MP+ patients showed that positive L858R status was associated with poorer RFS (HR 2.976; 95% CI 1.190-7.442; P = 0.020). CONCLUSIONS: EGFR L858R was more frequently harbored in the MP+ adenocarcinoma patients than in the MP- adenocarcinoma patients. Intense expression of L858R in the MP component was suggested, and the MP+ patients harboring L858R were at comparatively higher risk of recurrence in the group with pN0M0 lung adenocarcinoma.

Synchronicity of genetic variants between primary sites and metastatic lymph nodes, and prognostic impact in nodal metastatic lung adenocarcinoma.

PURPOSE: Nodal positive lung adenocarcinoma includes wide range of survival. Several methods for the classification of nodal-positive lung cancer have been proposed. However, classification considering the impact of targetable genetic variants are lacking. The possibility of genetic variants for the better stratification of nodal positive lung adenocarcinoma was estimated. METHODS: Mutations of 36 genes between primary sites and metastatic lymph nodes (LNs) were compared using next-generation sequencing. Subsequently, mutations in EGFR and BRAF, rearrangements in ALK and ROS1 were evaluated in 69 resected pN1-2M0 adenocarcinoma cases. Recurrence-free survival (RFS), post-recurrence survival (PRS), and overall survival (OS) were evaluated with respect to targetable variants and tyrosine kinase inhibitor (TKI) therapy after recurrence. RESULTS: About 90% of variants were shared and allele frequencies were similar between primary and metastatic sites. In 69 pN1-2M0 cases, EGFR/ALK were positive in primary sites of 39 cases and same EGFR/ALK variants were confirmed in metastatic LNs of 96.7% tissue-available cases. Multivariate analyses indicated positive EGFR/ALK status was associated with worse RFS (HR 2.366; 95% CI 1.244-4.500; P = 0.009), and PRS was prolonged in cases receiving TKI therapy (no post-recurrence TKI therapies, HR 3.740; 95% CI 1.449-9.650; P = 0.006). OS did not differ with respect to targetable variants or TKI therapy. CONCLUSIONS: Cases harbouring targetable genetic variants had a higher risk of recurrence, but PRS was prolonged by TKI therapy. Classification according to the targetable genetic status provides a basis for predicting recurrence and determining treatment strategies after recurrence.

Multichannel transmission of intensity- and phase-modulated signals by optical phase conjugation using a quantum-dot semiconductor optical amplifier.

We report the demonstration of optical phase conjugation using a quantum-dot semiconductor optical amplifier. The transmission performance of wavelength-multiplexed 10-Gbit/s intensity- and phase-modulated signals is investigated for different channel alignments. In a 100-km transmission, we have successfully achieved high transmission performance with low power penalties for all the transmitted signals.

Generation of multi-wavelength picosecond pulses with tunable pulsewidth and channel spacing using a Raman amplification-based adiabatic soliton compressor.

We experimentally demonstrate pulsewidth-tunable picosecond multi-wavelength pulse generation at 10 Gb/s by the use of a Raman amplification-based adiabatic soliton compressor (RA-ASC). Multi-wavelength seed pulse trains are generated by a commercially available electroabsorption modulator and then compressed by using the RA-ASC. The pulsewidths of the compressed pulses can be simultaneously controlled from 16.0 ps to 2.0 ps by adjusting Raman pump power. Operating wavelength range of our scheme are also investigated, showing the possibility for wide channel spacing operations.

Polarization-insensitive and widely tunable wavelength conversion for polarization shift keying signal based on four wave mixing in highly non-linear fiber.

A fiber-based polarization-insensitive and widely tunable all-optical wavelength conversion for polarization shift keying (PolSK) signal is experimentally demonstrated by means of four-wave-mixing (FWM) in highly non-linear fiber. Polarization sensitivity of our scheme is compared with the conventional one and the conversion performance of the PolSK signal is investigated. In our scheme, preservation of state of polarization (SOP) of input PolSK signal is possible on both of the converted spectral components in FWM spectrum. In addition, over 23 nm of wavelength tunable operation with high conversion performance is achieved and detailed bit-error-rate (BER) characteristics are measured for both the up- and down-converted signal.

Wideband wavelength-flexible all-optical signal regeneration using gain-band tunable Raman amplification and self-phase-modulation-based spectral filtering.

We demonstrate operating wavelength-flexible all-optical signal regeneration with 80 nm wavelength range by simply controlling the pump wavelength of the Raman preamplifier and the passband of broadened signal spectral filtering. In the operating wavelength range, improvements in receiver sensitivity of more than 2.2 dB are successfully achieved.

Multiple-channel optical signal processing with wavelength-waveform conversions, pulsewidth tunability, and signal regeneration.

A multiple-channel multiple-function optical signal processor (MCMF-OSP) including wavelength-waveform conversions, pulsewidth tunability, and signal regeneration is realized through AND logic gate based on optical parametric processing with a pulsewidth-tunable RZ clock pump. The proposed scheme simultaneously offers four signal processing functions which are useful in wavelength-division multiplexing (WDM) transmission systems, and at network nodes with the necessity for multiple-channel data processing. After the discussions on the concept of MCMF-OSP, a proof-of concept experiment is demonstrated on four 10 Gb/s nonreturn-to-zero (NRZ) data format channels using nonlinearities in semiconductor optical amplifier (SOA) and highly nonlinear fiber (HNLF). A wavelength and waveform conversions to return-to-zero (RZ) modulation format are obtained together with pulsewidth-tunable range from 20% to 80% duty cycles for all input signals. The converted signals inherit the timing and waveform of the RZ clock pump, thus resulting in a time regeneration and large tolerance to narrow-band optical filtering (NAOF) and fiber accumulated chromatic dispersion (CD).

Transmission performance of a wavelength and NRZ-to-RZ format conversion with pulsewidth tunability by combination of SOA- and fiber-based switches.

An all-optical signal processing scheme coupling wavelength conversion and NRZ-to-RZ data format conversion with pulsewidth tunability into one by combination of SOA- and fiber-based switches, is experimentally demonstrated, and its transmission performance is investigated. An 1558 nm NRZ data signal is converted to RZ data format at 1546 nm with widely tunable pulsewidth from 20 % to 80 % duty cycle at the bit-rate of 10 Gb/s. The investigation on transmission performance of the converted RZ signals at each different pulsewidth is carried out over various standard single-mode fiber (SSMF) links up to 65 km long without dispersion compensation. The results clarify a significant improvement on transmission performance of converted signal in comparison with the conventional NRZ signal through tunable pulsewidth management and show the existence of an optimal pulsewidth for the RZ data format at each transmission distance with particular cumulative dispersion. The optimal pulsewidths of the converted RZ signal and its corresponding power penalties against the NRZ signal are also investigated in different SSMF links.

Broadband regenerative wavelength conversion and multicasting using triple-stage semiconductor-based wavelength converters.

We demonstrate broadband wavelength conversion with a 320 nm operating wavelength range and channel spacing flexible wavelength-division-multiplexing (WDM) multicasting from a 1550 nm signal using a triple-stage cascaded semiconductor-optical-amplifier-based wavelength converter.

Discrete wavelength tuning characteristics of a single-frequency fiber laser with dual-wavelength external frequency-stable light injection.

We investigate discrete wavelength tuning characteristics of a single-frequency fiber laser locked to either of two external lights. Frequency locking is achieved by the cooperatively induced spatial-hole burning (SHB) of a saturable absorber in the laser cavity. We show that lasing frequency is well locked to either of the two external lights when the lasing wavelength of the fiber laser is adjusted to the corresponding wavelength of the external light by tuning the bandpass filter in the laser cavity. The locked frequency stability of the fiber laser is as high as that of the employed external light source.

Performance improvement of optical RZ-receiver by utilizing an all-optical waveform converter.

A practical receiver scheme with all-optical waveform conversion is proposed and demonstrated. To mitigate influence of the timing jitter of the received signal, the proposed receiver employs a semiconductor optical amplifier (SOA)-based waveform converter, which can generate signal pulses with a rectangular-like profile. We have evaluated the receiver performances of the conventional and proposed schemes. The receiver sensitivity improvement of 0.7 dB and the phase-margin enlargement of 60 % were simultaneously achieved in comparison with the conventional receiver scheme.

Performances of a widely pulsewidth-tunable multiwavelength pulse generator by a single SOA-based delayed interferometric switch.

Performances of a multiwavelength optical pulse generator by utilizing a single semiconductor optical amplifier (SOA)-based delayed interferometric switch are investigated. The generator enables us to generate multiwavelength clock pulse trains, which are synchronized with an optical clock. Moreover, the output waveform can be easily controlled by adjusting the time delay and phase offset of the interferometric switch. The obtained pulsewidth controllability is also useful to optimize the waveform according to transmission lines with different cumulative dispersions. We have verified that the pulsewidth tuning enables us to optimize transmission characteristics with various cumulative dispersion values, and have successfully obtained the improved transmission performances of the waveform-converted signals in comparison with conventional signals.

Photochemical ligation of DNA "words" for DNA computing.

The photochemical DNA computing of 5-vinyluracil ((V)U) containing oligodeoxynucleotides (ODNs) tethered multiple "DNA words" is demonstrated. A new MARK and UNMARK operation based on the (V)U mediated reversible DNA photoligation has been developed for multiple-word DNA computing. The utility of this operation for DNA computing is demonstrated by solving a small Satisfiability problem (SAT problem) in which information was encoded in three tandem words.

All-optical wavelength and pulse-width conversions with a Sagnac interferometer semiconductor-based switch.

A Sagnac interferometer switch with a semiconductor optical amplifier is proposed for all-optical wavelength and pulse-width conversions. The configuration of this switch is simple, and the switching speed is not limited by the semiconductor carrier's recovery time. The pulse width of the input data, 1.5 ps, is converted to 2.4-18.1 ps. A wavelength conversion of input data at 1539 nm to a tunable-wavelength bandwidth of 15 nm (1550-1565 nm) is also demonstrated.

Continuum spectrum generation utilizing adiabatic compression in Raman amplifier for multi-wavelength pulse source.

We have demonstrated a continuum spectrum generation utilizing adiabatic compression in Raman amplifier. Continuum medium consists of only dispersion-shifted fiber as a counter-pumped Raman gain medium. The power uniformity of the continuum spectrum can be improved by adjusting wavelength and power of the Raman pump source. A 16-nm-wide uniform continuum spectrum with the power fluctuation less than 3 dB is generated from an 18.0 ps pulse-width seed pulse produced by an electroabsorption modulator.