2009 Jan; 394(1): 105-113."

A Strong Neutrophil Elastase Proteolytic Fingerprint Marks the Carcinoma Tumor Proteome

Proteolytic cascades are deeply involved in critical stages of cancer progression. During the course of peptide-wise analysis of shotgun proteomic data sets representative of colon adenocarcinoma (AC) and ulcerative colitis (UC), we detected a cancer-specific proteolytic fingerprint composed of a set of numerous protein fragments cleaved C-terminally to V, I, A, T, or C residues, significantly overrepresented in AC. A peptide set linked by a common VIATC cleavage consensus was the only prominent cancer-specific proteolytic fingerprint detected. This sequence consensus indicated neutrophil elastase as a source of the fingerprint. We also found that a large fraction of affected proteins are RNA processing proteins associated with the nuclear fraction and mostly cleaved within their functionally important RNA-binding domains. Thus, we detected a new class of cancer-specific peptides that are possible markers of tumor-infiltrating neutrophil activity, which often correlates with the clinical outcome. Data are available via ProteomeXchange with identifiers: PXD005274 (Data set 1) and PXD004249 (Data set 2). Our results indicate the value of peptide-wise analysis of large global proteomic analysis data sets as opposed to protein-wise analysis, in which outlier differential peptides are usually neglected.

Spinal endodermal cyst resembling an arachnoid cyst in appearance: Pitfalls in intraoperative diagnosis of cystic lesions

BACKGROUND

Surgical treatment of endodermal cysts requires total removal of the cyst wall during the first operation to prevent recurrence. Therefore, intraoperative pathological diagnosis plays an important role in determining the optimal surgical strategy. We present a rare case of a spinal endodermal cyst and discuss its diagnostic difficulty during the intraoperative pathological examination.

CASE DESCRIPTION

An 18-year-old male presented with progressive paraparesis and precordial oppression. Magnetic resonance (MR) imaging revealed an intradural extramedullary cystic mass having the same signal intensity as cerebrospinal fluid (CSF) without gadolinium enhancement at the T1-T2 level. The preoperative diagnosis was an endodermal or arachnoid cyst. The patient underwent surgery. An intraoperative frozen section showed a cyst wall consisting of loose, thin, fibrous tissue intermittently covered by flattened epithelium. The diagnosis was an arachnoid cyst. Accordingly, partial resection of the cyst wall was performed to create CSF communication between the cyst and subarachnoid space. However, the postoperative pathological diagnosis from permanent sections was an endodermal cyst, which was lined with ciliated columnar epithelium that was immunopositive for cytokeratin and epithelial membrane antigen. Subsequent paraffin embedding and immunostaining of the intraoperative frozen sample also confirmed patchy cytokeratin expression by all flattened epithelial cells. The patient's cyst had refilled 10 months after surgery, and he subsequently underwent fenestration of the cyst wall and placement of a cyst-subarachnoid shunt.

CONCLUSION

Examination of multiple samples from multiple sites or intraoperative immunostaining of frozen sections is recommended for accurate intraoperative diagnosis of endodermal cysts.