Faculty Bibliography

Phosphatase and tensin homologue (PTEN) protein levels are critical for tumor suppression. However, the search for a recurrent cancer-associated gene alteration that causes PTEN degradation has remained futile. In this study, we show that Importin-11 (Ipo11) is a transport receptor for PTEN that is required to physically separate PTEN from elements of the PTEN degradation machinery. Mechanistically, we find that the E2 ubiquitin-conjugating enzyme and IPO11 cargo, UBE2E1, is a limiting factor for PTEN degradation. Using in vitro and in vivo gene-targeting methods, we show that Ipo11 loss results in degradation of Pten, lung adenocarcinoma, and neoplasia in mouse prostate with aberrantly high levels of Ube2e1 in the cytoplasm. These findings explain the correlation between loss of IPO11 and PTEN protein in human lung tumors. Furthermore, we find that IPO11 status predicts disease recurrence and progression to metastasis in patients choosing radical prostatectomy. Thus, our data introduce the IPO11 gene as a tumor-suppressor locus, which is of special importance in cancers that still retain at least one intact PTEN allele.

The Cullin-RING ubiquitin ligase 4 (CRL4) is implicated in controlling cell cycle, DNA damage repair, and checkpoint response based on studies employing cell lines and mouse models. CRL4 proteins, including CUL4A and CUL4B, are often highly accumulated in human malignancies. Elevated CRL4 attenuates DNA damage repair and increases genome instability that is believed to facilitate tumorigenesis. However, this has yet to be evaluated in human patients with cancer. In our study, 352 lung cancer and 62 normal lung specimens of Asian origin were constructed into tissue microarrays of four distinct lung cancer subtypes. Expression of CUL4A, CUL4B, and their substrates was detected by immunohistochemistry and analyzed statistically for their prognostic value and association with DNA damage response and genomic instability. Our results show that both CUL4A and CUL4B are overexpressed in the majority of lung carcinomas (PCUL4A <0.001 and PCUL4B <0.001) and significantly associated with tumor size (PCUL4A <0.001 and PCUL4B = 0.002), lymphatic invasion (PCUL4A = 0.004 and PCUL4B <0.001), metastasis (PCUL4A = 0.019 and PCUL4B = 0.006), and advanced TNM stage (PCUL4A <0.001 and PCUL4B <0.001), which parallels gene amplification and abnormal activation of the canonical WNT signaling. Moreover, overexpression of CUL4A, but not CUL4B, is significantly associated with tobacco smoking (p = 0.01) and is inversely correlated with XPC and P21, both of which are substrates of CUL4A (PCUL4A = 0.019 and PCUL4B = 0.006). Higher levels of CUL4A or CUL4B are significantly associated with the overall survival of patients (PCUL4A <0.001 and PCUL4B <0.001) and progression-free survival (PCUL4A <0.001 and PCUL4B = 0.001). Our findings revealed that CUL4A and CUL4B are differentially associated with etiologic factors for pulmonary malignancies and are independent prognostic markers for the survival of distinct lung cancer subtypes.

A high suspicion for relapsed metastatic disease must arise when an intracardiac mass is detected in a patient with a recent history of Ewing sarcoma. Nevertheless, the scenario may eventually turn out to be much more complex than expected, and the possibility that the intracardiac tumor may instead be a "second" primary sarcoma, although extremely rare, should also be considered. We describe the first case of concomitant diagnosis of Ewing sarcoma and low-grade myxoid spindle cell sarcoma in the same young patient.

BACKGROUND: Pericardial effusions can cause considerable morbidity and potentially may lead to mortality. Malignant pericardial effusions are uncommon, and data on malignancies encountered in pericardial effusion cytology specimens are limited. METHODS: Relevant records of all pericardial effusions from January 2008 to September 2014 were examined and compared with pericardial biopsy results when performed. Discrepant cases were reviewed to determine the cause of the disagreement. RESULTS: In total, 419 pericardial effusion specimens obtained from 364 patients were examined. Cytologic diagnostic categories included: negative for malignancy (332 specimens; 79%), equivocal (25 specimens; 6%), and positive (62 specimens from 51 patients; 15%). Forty-seven patients who had positive effusions were known to have malignancy. The most common primary malignancies were breast (39.3%) and lung (39.3%) cancers in women and lung cancer (47.4%) in men. A concurrent pericardial biopsy was performed in 46% of patients. Excluding equivocal cytologic diagnoses, cytology and biopsy were concordant in 153 of 173 paired samples (88.4%). The sensitivity of cytology in diagnosing malignancy was 92.1% compared with 55.3% for pericardial biopsy. CONCLUSIONS: Cytologic examination has significant diagnostic utility in the evaluation of pericardial effusions and exhibits a lower false-negative rate compared with pericardial biopsy. Submission of pericardial biopsy alongside effusion cytology is associated with increased sensitivity for detecting malignancy and may be especially useful in the setting of low-volume pericardial effusion. Cancer Cytopathol 2017;125:128-137. (c) 2016 American Cancer Society.

Molecularly targeted therapies benefit approximately 15-20% of non-small cell lung cancer (NSCLC) patients carrying specific drug-sensitive mutations. Thus, there is a clinically unmet need for the identification of novel targets for drug development. Here, we performed RNA-deep sequencing to identify altered gene expression between malignant and non-malignant lung tissue. Matrix Metalloproteinase 14 (MMP14), a membrane-bound proteinase, was significantly up-regulated in the tumor epithelial cells and intratumoral myeloid compartments in both mouse and human NSCLC. Overexpression of a soluble dominant negative MMP14 (DN-MMP14) or pharmacological inhibition of MMP14 blocked invasion of lung cancer cells through a collagen I matrix in vitro and reduced tumor incidence in an orthotopic K-RasG12D/+p53-/- mouse model of lung cancer. Additionally, MMP14 activity mediated proteolytic processing and activation of Heparin-Binding EGF-like Growth Factor (HB-EGF), stimulating the EGFR signaling pathway to increase proliferation and tumor growth. This study highlights the potential for development of therapeutic strategies that target MMP14 in NSCLC with particular focus on MMP14-HB-EGF axis.