Project description:Invasive mucinous adenocarcinoma (IMA) is a rare subtype of lung adenocarcinoma with a poor prognosis. Compared to non-small cell lung cancer (NSCLCs), IMA more frequently harbors KRAS mutations in the order KRAS p.G12V, p.G12D, and p.G12C. This report describes a patient with KRAS p.G12C-mutant IMA treated with sotorasib. To date, no studies have investigated the therapeutic efficacy or resistance mechanisms of sotorasib in IMA. The patient was treated with carboplatin and pemetrexed, followed by sotorasib upon disease progression. While the primary lung lesions responded well, metastatic thoracic lymph node lesions continued to increase. A pathological autopsy was performed with the family’s consent to investigate potential resistance mechanisms. RNA sequencing and additional analyses revealed increased VEGF-A expression in metastatic lymph node lesions, suggesting a role in sotorasib resistance. These findings provide insights into the molecular mechanisms underlying treatment resistance in KRAS p.G12C-mutant IMA.
Project description:Profound changes in cancer cell identity can alter malignant potential and therapeutic response. Loss of the pulmonary lineage specifier NKX2-1 augments the growth of KRAS-driven lung adenocarcinoma and causes pulmonary to gastric transdifferentiation. Here we show that the transcription factors FoxA1 and FoxA2 are required for initiation of mucinous NKX2-1-negative lung adenocarcinomas in the mouse and for activation of their gastric differentiation program. Foxa1/2 deletion severely impairs tumor initiation and causes a proximal shift in cellular identity, yielding tumors expressing markers of the squamocolumnar junction of the gastrointestinal tract. In contrast, stochastic loss of FoxA1/2 expression in NKX2-1-negative tumors is associated with keratinizing squamous differentiation. Using sequential in vivo recombination, we find that FoxA1/2 loss in established KRAS-driven neoplasia is sufficient for direct induction of keratinizing squamous cell carcinomas in the lung. Thus, NKX2-1, FoxA1 and FoxA2 coordinately regulate the growth and identity of lung adenocarcinoma in a context-specific manner.
Project description:The endoderm-lineage transcription factor FOXA2 has been shown to inhibit lung tumorigenesis in in vitro and xenograft studies using lung cancer cell lines. However, FOXA2 expression in primary lung tumors does not correlate with an improved patient survival rate, and the functional role of FOXA2 in primary lung tumors remains elusive. To understand the role of FOXA2 in primary lung tumors in vivo, here, we conditionally induced the expression of FOXA2 along with either of the two major lung cancer oncogenes, EGFRL858R or KRASG12D, in the lung epithelium of transgenic mice. Notably, FOXA2 suppressed autochthonous lung tumor development driven by EGFRL858R, whereas FOXA2 promoted tumor growth driven by KRASG12D. Importantly, FOXA2 expression along with KRASG12D produced invasive mucinous adenocarcinoma (IMA) of the lung, a fatal mucus-producing lung cancer comprising approximately 5% of human lung cancer cases. In the mouse model in vivo and human lung cancer cells in vitro, FOXA2 activated a gene regulatory network involved in the key mucous transcription factor SPDEF and upregulated MUC5AC, whose expression is critical for inducing IMA. Coexpression of FOXA2 with mutant KRAS synergistically induced MUC5AC expression compared with that induced by FOXA2 alone. ChIP-seq combined with CRISPR interference indicated that FOXA2 bound directly to the enhancer region of MUC5AC and induced the H3K27ac enhancer mark. Furthermore, FOXA2 was found to be highly expressed in primary tumors of human IMA. Collectively, this study reveals that FOXA2 is not only a biomarker but also a driver for IMA in the presence of a KRAS mutation.SignificanceFOXA2 expression combined with mutant KRAS drives invasive mucinous adenocarcinoma of the lung by synergistically promoting a mucous transcriptional program, suggesting strategies for targeting this lung cancer type that lacks effective therapies.
Project description:Profound changes in cancer cell identity can alter malignant potential and therapeutic response. Loss of the pulmonary lineage specifier NKX2-1 augments the growth of KRAS-driven lung adenocarcinoma and causes pulmonary to gastric transdifferentiation. Here we show that the transcription factors FoxA1 and FoxA2 are required for initiation of mucinous NKX2-1-negative lung adenocarcinomas in the mouse and for activation of their gastric differentiation program. Foxa1/2 deletion severely impairs tumor initiation and causes a proximal shift in cellular identity, yielding tumors expressing markers of the squamocolumnar junction of the gastrointestinal tract. In contrast, stochastic loss of FoxA1/2 expression in NKX2-1-negative tumors is associated with keratinizing squamous differentiation. Using sequential in vivo recombination, we find that FoxA1/2 loss in established KRAS-driven neoplasia is sufficient for direct induction of keratinizing squamous cell carcinomas in the lung. Thus, NKX2-1, FoxA1 and FoxA2 coordinately regulate the growth and identity of lung adenocarcinoma in a context-specific manner.
Project description:The aim of the study was to investigate gene expression tumour progression of KRas*/MYC driven lung tumours from adenocarcinoma in situ to invasive disease.
Project description:Introduction: Mucinous tumors are the second most common form of epithelial ovarian tumor, yet the cell of origin for this histological sub-type remains undetermined. While these tumors are thought to arise through a stepwise progression from benign cystadenoma to borderline tumor to invasive carcinoma, few studies have attempted to comprehensively characterize the genetic changes specific to this subtype or its precursors. Methods: To explore the spectrum of genomic alterations common to mucinous tumors we performed high resolution genome-wide copy number analysis, mutation screening by Sanger sequencing and immunohistochemistry on a series of primary ovarian mucinous cystadenomas (n=20) and borderline tumors (n=22). Results: Integration of copy number data, targeted mutation screening of RAS/RAF pathway members and immunohistochemistry reveals that p16 loss and RAS/RAF pathway alterations are highly recurrent events that occur early during mucinous tumor development. The frequency of concurrence of these events was observed in 40% of benign cystadenomas and 68% of borderline tumors. Conclusions: This study is the largest and highest resolution analysis of mucinous benign and borderline tumors performed to date and provides strong support for these lesions being precursors of primary ovarian mucinous adenocarcinoma. The high level of uniformity in the molecular events underlying the pathogenesis of mucinous ovarian tumors provides an opportunity for treatments targeting specific mutations and pathways. Copy number data was generated for 42 mucinous ovarian tumours (20 benign, 22 borderline). Epithelial and stromal DNA from the tumours and matched-normal lymphocyte DNA were all analysed. Processed/normalized data for the germline DNA samples are not provided because they themselves are normalised to a diploid copy number, making all the probe values 2, which is not informative.