An exploration of pathways involved in lung carcinoid progression using gene expression profiling

Abstract

Pulmonary carcinoids comprise a well-differentiated subset of neuroendocrine tumors usually associated with a favorable prognosis, but mechanisms underlying disease progression are poorly understood. In an explorative approach to identify pathways associated with progression, we compared gene expression profiles of tumors from five patients with a favorable and five with a poor disease outcome. Differentially expressed genes were validated using quantitative real-time PCR on 65 carcinoid tumors, in combination with survival analysis. One of the identified pathways was further examined using immunohistochemistry. As compared with other chromosomal locations, a significantly higher number of genes downregulated in carcinoids with a poor prognosis were located at chromosome 11q (P = 0.00017), a region known to be frequently lost in carcinoids. In addition, a number of upregulated genes were found involved in the mitotic spindle checkpoint, the chromosomal passenger complex (CPC), mitotic kinase CDC2 activity and the BRCA-Fanconi anemia pathway. At the individual gene level, BIRC5 (survivin), BUB1, CD44, IL20RA, KLK12 and OTP were independent predictors of patient outcome. For survivin, the number of positive nuclei was also related to poor prognosis within the group of carcinoids. Aurora B kinase and survivin, major components of the CPC, were particularly upregulated in high-grade carcinomas and may therefore comprise therapeutic targets for these tumors. To our knowledge, this is the first expression profiling study focusing specifically on pulmonary carcinoids and progression. We have identified novel pathways underlying malignant progression and validated several genes as being strong prognostic indicators, some of which could serve as putative therapeutic targets.

Identification of MicroRNAs Differentially Expressed in Lung Carcinoid Subtypes and Progression

“…MiR-431-5p has never been associated with metastatic properties so far, while miR-409, with special reference to miR-409-3p, has been shown to inhibit cell migration and/or invasion in fibrosarcoma [17], bladder cancer [18] and gastric cancer [19] cells. Our findings shed light on molecular anomalies associated with lymph node dissemination of lung carcinoids and might prove to add clinically relevant prognostic information to the traditional mitotic count and presence of necrosis parameters [7,20,21]. In fact, predictive in silico analysis of genes targeted by the 3 microRNAs associated with metastatic disease revealed that all 3 microRNAs modulate similar cellular functions.…”

Ki-67 labeling index of neuroendocrine tumors of the lung has a high level of correspondence between biopsy samples and surgical specimens when strict counting guidelines are applied

“…This methodological study paves the way to the use of Ki-67 LI in a daily diagnostic setting to characterize metastatic lung NET [21,33,38]. On surgical specimens of lung NET, some methodological studies on quantification of Ki-67 staining to generate a Ki-67 LI by manual or automated analysis systems have been performed [17,19,32,[39][40][41]. None, however, compared biopsies with corresponding surgical specimens, probably because in these tumors, the Ki-67 LI is not used for diagnosis or grading or as a prognostic factor [4,6,30], as morphology remains the favored approach [3].…”

“…In metastatic lung NET, the importance of the Ki-67 LI on biopsy samples is not so much the diagnosis as such (which paradoxically matters less once high-grade NET has been excluded) but rather to guide subsequent therapy choice [33]. This molecular, morphological, and clinical heterogeneity of lung NET [20,39,[46][47][48][49][50] is similar to that of G3 GEP NET for which the Ki-67 LI is of equal diagnostic importance [26,[51][52][53][54][55][56]. Of note, LCNECs of the lung show a wide range of histological and molecular features, as some cases are morphologically close to SCCs [13, 14,16,47], while others are closer to conventional non-small cell carcinoma [47,[57][58][59]] and yet others to AC [3,8,47].…”

BUB1 mRNA is significantly co-expressed with AURKA and AURKB mRNA in advanced-stage ovarian serous carcinoma

“…In the present study, we found no association between Bub1 mRNA and protein levels and chemoresponse or survival. However, Bub1 expression has been associated with aggressive clinical behavior in other cancers, including breast carcinoma, endometrial carcinoma, malignant melanoma, and pulmonary carcinoid [28][29][30][31][32]. Whether Bub1 may have such role in early-stage serous OC or in other histological subtypes of OC remains to be determined.…”