[Clinicopathological features of second primary lung cancer and pulmonary metastasisin patients with breast cancer].

Objective: To compare the clinicopathological characteristics of second primary lung cancer following breast cancer and lung metastases from breast cancer, and then to analyze the risk factors in breast cancer patients with second primary lung tumor. Methods: Clinical data of 55 breast cancer patients with second primary lung tumor and 205 breast cancer patients with solitary pulmonary metastasis in Shandong Cancer Hospital from January 2006 to January 2017 were retrospectively analyzed. The risk factors of primary lung cancer following breast cancer were analyzed using logistic regression model. Results: Second primary lung cancer in patients with first breast cancer accounted for approximately 21.2%(55/260) of pulmonary malignant solitary nodules, and 0.84%(55/6 580) of all breast cancer patients. The median intervals between the diagnosis of second primary lung cancer or lung metastasis and first breast cancer were 52 months and 42 months, respectively. These two groups showed significant difference between age, time interval between diagnoses, breast tumor size, axillary lymph node metastasis, estrogen receptor, molecular subtype (luminal B and triple-negative) and history of radiotherapy (P<0.05 for all). A multivariate logistic regression model confirmed that age (OR=1.088, P<0.001), breast tumor size(OR=0.480, P<0.001), and radiotherapy history (OR=3.460, P=0.004) were all independent factors for second primary lung cancer. Conclusions: For isolated pulmonary nodules in patients with breast cancer, especially for those with elder age, larger tumor size and radiotherapy history, we should distinguish the second primary lung cancer from pulmonary metastasis. The treatment regimen for lung metastasis and primary lung cancer in patients with breast cancer are entirely distinct. The timely histopathology examinations for pulmonary nodes in patients with breast cancer are recommended.

[Effect of autophagy inhibitor combined with EGFR inhibitor on triple-negative breast cancer MDA-MB-468 and MDA-MB-231 cells].

OBJECTIVE: To investigate the effect of combined administration of autophagy inhibitor 3-methyladenine/bafilomycin A1 and EGFR inhibitor gefitinib on triple-negative breast cancer MDA-MB-468, MDA-MB-231 cells and estrogen receptor-positive MCF-7 cells. METHODS: All the cells were treated with 3-methyladenine/bafilomycin A1 and/or gefitinib. The effect of autophagy inhibitor and gefitinib on the cell growth was evaluated by MTT assay. Cell apoptosis was detected by flow cytometry. Western blot analysis was used to determine the alteration of autophagy-related protein (such as LC3) and apoptosis-related proteins (such as caspase-3 and caspase-9). RESULTS: MTT assay showed that the IC50 in the GE+ 3-MA and GE+ BAF groups were (4.1±0.2) µmol/L and (3.8±0.3) µmol/L, significantly lower than that of the gefitinib alone group [(7.0±0.2) µmol/L] in MDA-MB-468 cells (P<0.05). Similarly, the IC50 in the GE+ 3-MA and GE+ BAF groups were (9.7±0.1) µmol/L and (7.7±0.2) µmol/L, significantly lower than that of the gefitinib alone group [(14.7±0.1) µmol/L]in MDA-MB231 cells (P<0.05). The flow cytometry assay revealed that the apoptosis rates of MDA-MB-468 cells in GE, GE+ 3-MA and GE+ BAF groups were (12.43±3.18)%, (23.37±2.71)% and (18.71±2.81)%, respectively. The apoptosis rates of MDA-MB-231 cells of the GE, GE+ 3-MA and GE+ BAF groups were (12.15±1.82)%, (16.94±2.19)% and (33.83±5.92) %, significantly higher than that of the gefitinib alone group (All P<0.05). The apoptosis rates of the MCF-7 cells were not changed significantly among the three groups (P>0.05). Western blot data showed that the expression levels of LC3 and p-Akt were decreased in the combined groups than that of the gefitinib alone group, while the p-PTEN, caspase-3 and caspase-9 were increased. CONCLUSIONS: Autophagy inhibitor may enhance the sensitivity to gefitinib in MDA-MB-468 and MDA-MB-231 cells by activation of the PTEN/P13K/Akt pathway. Apoptosis in MDA-MB-468 and MDA-MB-231 cells might be enhanced by the combination treatment through caspase cascade.