BackgroundPembrolizumab has significantly improved outcomes in patients with advanced non-small cell lung cancer. Combining programmed death-1 inhibitor with stereotactic body radiotherapy showed a slight toxicity and good benefits in recent clinical trials. However, patients infected with human immunodeficiency virus were excluded from most trials because it was assumed that their anti-tumor immunity was compromised compared with immunocompetent patients.Case presentationIn June 2016, a 52-year-old Chinese man presented with human immunodeficiency virus and lung adenocarcinoma (T1bN3M1b). From November 2016 to December 2016, systemic chemotherapy and palliative radiotherapy for bone metastasis of femoral neck were carried out, but the tumor progressed. In January 2017, after immunochemistry detection of programmed death-1 and programmed death-ligand 1 expression (both > 50%), pembrolizumab was started. Three weeks after pembrolizumab, we combined stereotactic body radiotherapy for the primary lung tumor. He received no comfort and his CD4 lymphocyte count was stable. Human immunodeficiency virus-ribonucleic acid remained below the limits of detection. In March 2017, after three cycles of pembrolizumab and 5 weeks of stereotactic body radiotherapy therapy, he suddenly presented with palpitations. Emergency computed tomography scanning showed massive pericardial effusion and interstitial pneumonia. So we interrupted the pembrolizumab use and initiated treatment with prednisolone 1 mg/kg; however, the tumor progressed. Then, his CD4 lymphocyte count declined. Finally he died in June 2017 due to dyscrasia.ConclusionsPembrolizumab combined with SBRT therapy for patients with human immunodeficiency virus infection and non-small cell lung cancer may lead to serious immune-related adverse events and more clinical trials are needed.

p62 protein has been implicated in bone metastasis and is a multifunctional adaptor protein usually correlated with autophagy. Herein, we investigated p62 expression and its prognostic significance in bone metastasis of lung adenocarcinoma, and analyzed whether the mechanism involved depends on autophagy. mRNA and protein expression of p62, LC3B and Beclin 1 were detected by reverse transcription-quantitative PCR and western blotting, respectively, in fresh bone metastasis tissues (n=6 cases) and normal cancellous bone tissues (n=3 cases). The association between p62 and LC3B expression and patient prognosis was subsequently analyzed in 62 paraffin-embedded bone metastasis specimens by immunohistochemistry assay. Small interfering RNA (siRNA) was employed to downregulate p62 expression in SPC-A-1 and A549 cells. Cell proliferation and migration ability were tested by CCK8, CCF and Transwell assays respectively. Autophagy was induced by Rapamycin or inhibited by Atg 7 knockout/Chloroquine in A549 cells and p62 and LC3II/I expression were analyzed. After subcutaneous inoculation or intracardial injection of A549 cells into nude mice, the effect of p62 downregulation in vivo was analyzed by histopathological examination. The results showed that p62, LC3B and Beclin 1 mRNA and protein were all overexpressed in bone metastasis tissues (all P<0.01). Patient samples with high p62 expression levels were significantly associated with more bone lesions (>3), shorter overall survival rates and shorter progression free survival rates compared with patients having lower p62 expression (P=0.014, P=0.003, P=0.048, respectively). Cox regression analysis identified p62 expression as an independent prognostic indicator of overall survival of patients with bone metastasis (P=0.007). In vitro p62 downregulation inhibited SPC-A-1 and A549 cells migration but had no effect on cell proliferation. After autophagy induction or inhibition, p62 expression involved in autophagy flux and changed inconsistently according to the switch of LC3I to LC3II in different autophagy conditions. In vivo p62 downregulation had no effect on growth of subcutaneous tumor. Lung or bone metastasis lesion was not found in all mice model. These findings suggested that p62 overexpression promotes tumor cell invasion out of LC3-dependent autophagy, which could be used a potential prognostic biomarker and therapeutic target for bone metastasis of lung adenocarcinoma.

Giant cell tumor of bone (GCTB) is an intermediate (locally aggressive) bone tumor with a recurrence rate of >30% following surgery. GCTB recurrence is ultimately due to the proliferation of neoplastic stromal (NS) cells. However, the precise mechanism underlying the regulation of NS cell proliferation remains unknown. p62 protein is a multifunctional adaptor protein that exerts a positive role in bone tumors and metabolic bone diseases. In the present study, the mRNA and protein expression levels of p62 were detected by reverse transcription-quantitative PCR and western blotting, respectively, in 8 paired fresh GCTB tumor tissues and adjacent normal cancellous bone tissues. The association between p62 expression level and patient prognosis was subsequently analyzed in 54 paraffin-embedded tumor specimens by immunohistochemistry assay. NS cells were isolated from GCTB primary cell culture, and the role of p62 was evaluated using in vitro cell proliferation, migration and invasion assays. The results revealed that p62 mRNA and protein were overexpressed in tumor tissues. High p62 expression levels were significantly associated with the recurrence of GCTB (P=0.001). The patients in the high p62 expression group had shorter 5-year recurrence-free survival rates compared with the patients in the low p62 expression group (P<0.001). Cox regression analysis identified p62 expression as an independent prognostic indicator of the recurrence-free survival of patients with GCTB (P<0.001). The in vitro experiments revealed that p62 downregulation inhibited NS cell proliferation, invasion and migration, and promoted apoptosis. In conclusion, it was found that p62 overexpression is associated with the recurrence of GCTB via the promotion of NS cell proliferation. Therefore, p62 could be a novel prognostic indicator, and a potential therapeutic target for GCTB.