Clinical implication of HLA class I expression in breast cancer

<p>Abstract</p> <p>Background</p> <p>Human leukocyte antigen (HLA)-class I molecules on tumor cells have been regarded as crucial sites where cytotoxic T lymphocytes (CTL) can recognize tumor-specific antigens and are strongly associated with anti-tumor activity. However, the clinical impact of HLA class I expression in breast cancer has not been clarified.</p> <p>Methods</p> <p>A total of 212 breast cancer patients who received curative surgery from 1993 to 2003 were enrolled in the current study. HLA class I expression was examined immunohistochemically using an anti-HLA class I monoclonal antibody. The correlation between HLA class I positivity and clinical factors was analyzed.</p> <p>Results</p> <p>The downregulation of HLA class I expression in breast cancer was observed in 69 patients (32.5%). HLA class I downregulation was significantly associated with nodal involvement (p < 0.05), TNM stage (p < 0.05), lymphatic invasion (p < 0.01), and venous invasion (p < 0.05). Patients with preserved HLA class I had significantly better disease-free interval (DFI) than those with loss of HLA class I (p < 0.05). However, in multivariable analysis, HLA class I was not selected as one of the independent prognostic factors of disease-free interval.</p> <p>Conclusion</p> <p>The examination of HLA class I expression is useful for the prediction of tumor progression and recurrent risk of breast cancer via the antitumor immune system.</p

Low amplified spontaneous emission threshold and efficient electroluminescence from a carbazole derivatized excited-state intramolecular proton transfer dye

The search for new classes of efficient electroluminescent organic laser dyes with low amplified spontaneous emission (ASE) threshold (E) and low optical losses is crucial toward the realization of organic injection lasers. In this work, we report in-depth studies of an organic semiconducting laser dye, benzo[d]thiazol-2-yl)-5-(9H-carbazol-9-yl)phenol (HBT-Cz), and compare the photophysical study with its parent HBT dye. While HBT is not laser-active in solution, the carbazole derivatized dye (i.e., HBT-Cz) showed a low solution ASE threshold of 21 mJ/cm, which is comparable to a common high-performing commercial laser dye, Rhodamine 6G (Rh-6G). HBT-Cz also exhibited a low film ASE threshold of 2.4 μJ/cm with a low optical loss coefficient of 1.5 cm, which is the lowest waveguide loss coefficient reported for solution-processed organic semiconductors. Organic light-emitting diodes based on this material showed a high maximum EQE of 1.9%, which is close to the theoretical EQE limit of the emitter, and high brightness of >2,300 cd/m. Further insights into the lasing properties of the material were provided by steady state UV-visible spectroscopy, and transient absorption spectroscopy, shedding light on excited-state species absorption. To the best of our knowledge, this is the first report of a solution-processable organic small molecular dye, exhibiting a low ASE threshold and lowest optical loss coefficient, coupled with efficient electroluminescence

Solid cyclooctatetraene-based triplet quencher demonstrating excellent suppression of singlet–triplet annihilation in optical and electrical excitation

Triplet excitons have been identified as the major obstacle to the realisation of organic laser diodes, as accumulation of triplet excitons leads to significant losses under continuous wave (CW)\ua0operation and/or electrical excitation. Here, we report the design and\ua0synthesis of a solid-state organic triplet quencher, as well as in-depth studies of its dispersion into a solution processable bis-stilbene-based laser dye. By blending the laser dye with 20 wt% of the quencher, negligible effects on the ASE thresholds, but a complete suppression of singlet–triplet annihilation (STA) and a 20-fold increase in excited-state photostability of the laser dye under CW excitation, were achieved. We used small-area OLEDs (0.2 mm2) to demonstrate efficient STA suppression by the quencher in the\ua0nanosecond range, supported by simulations to provide insights into the observed STA quenching under electrical excitation. The results demonstrate excellent triplet quenching ability under both optical and electrical excitations in the nanosecond range, coupled with excellent solution processability

Low amplified spontaneous emission and lasing thresholds from hybrids of fluorenes and vinylphenylcarbazole

Organic semiconductor dyes have attracted high interest as laser gain media owing to their judicious features of solution processability, lightweight, high mechanical flexibility, high wavelength-tunability, and low-cost manufacture. In this work, fluorene-carbazolylstyryl hybrids are reported, SFCz and BSTFCz, as new solution processable organic semiconductor laser dyes to show high molar extinction coefficients (up to 1.98 x 10(5)dm(3)mol(-1)cm(-1)), high photoluminescence quantum yields (up to 81 +/- 4%), high radiative decay constants (up to 1.24 x 10(9)s(-1)), and low film amplified spontaneous emission thresholds (down to 0.70 mu J cm(-2)). By using mixed-order distributed feedback laser structures, extremely low lasing threshold of 0.5 mu J cm(-2)is achieved. To elucidate their electroluminescent properties, simple solution-processed organic light-emitting diodes based on the new materials are fabricated to show good external quantum efficiencies (2%) and high brightness (approximate to 2800 cd m(-2)). The results indicate the ease in material synthesis and fabrication enabling solution-processed low-threshold lasing toward future injection laser

Lasing operation under long-pulse excitation in solution-processed organic gain medium: toward CW lasing in organic semiconductors

High mechanical flexibility and wavelength tunability of organic semiconductor materials have propelled the development of organic semiconductor lasers (OSLs) as a complementary technology to current inorganic lasers. While excellent progress has been made across multiple aspects of OSLs, demonstration of long‐pulse operation [quasi‐continuous wave (qCW) or continuous wave (CW)] lasing has presented significant challenges due to the detrimental accumulation of triplets under long‐pulse photoexcitation and substantial quenching of singlet excitons, arising from singlet‐triplet annihilation (STA). In particular, qCW or CW lasing from solution‐processed OSL materials has not been reported, and thus remains a long‐thought objective in optoelectronic research. Using a novel bis(N‐carbazolylstyryl)‐9,9‐dihexylfluorene (BSFCz), the first solution‐processable organic laser dye demonstrating lasing oscillation in the long‐pulse photoexcitation regime (up to 10 ms pulse width) with a low threshold (420 W cm−2), which in part can be attributed to its negligible spectral overlap between triplet excited‐state absorption and laser emission, is herein reported. Temporal emission profiles below and above the lasing threshold also demonstrate that STA has a negligible effect on emission. These combined observations show\ua0BSFCz\ua0incur low losses due to triplet excited‐states, leading to extremely small changes in lasing thresholds when moving from pulsed to qCW (>1 ms) excitation