Correction to: High fascin-1 expression in colorectal cancer identifies patients at high risk for early disease recurrence and associated mortality

An amendment to this paper has been published and can be accessed via the original article.


Background
Tumor metastasis represents the major cause of cancer-associated mortality 1 , with a total of 53.200 2 new estimated deaths in 2020 among both sexes with regard to colorectal cancer (CRC). Metastasis, however, is a multi-step process wherein tumor cell migration and invasion are critical steps 3 so that a primary tumor may spread to a secondary tissue 4-6 . Cell migration and invasion proceeds when structural remodeling of the actin cytoskeleton occurs, by forming polymers and bundles to cause dynamic changes in cell shapes 7-9 . Filopodia represent finger-like plasma membrane protrusions whose formation results upon dynamic changes of the actin cytoskeleton 10 . Their role is fundamental regarding the regulation of cell shape and motility events 10 .
Fascin is the main actin cross-linker in filopodia 11 . Filopodia formation occurs after fascin binds to 10-30 parallel actin filaments together into straight, compact, and rigid bundles that provide further mechanical stiffness to actin bundles 10, 12 . Previous reports demonstrate that ectopic fascin expression in tumor cells promotes tumor cell migration, invasion, and metastasis tumor cell migration, invasion, and metastasis 13 . In addition, the upregulation of fascin correlates with the EMT (epithelial to mesenchymal transition) pathway 14 . In this background, the present study aimed to investigate the expression patterns of fascin-1 in CRC and to assess its clinical importance. Patients that underwent a curative surgical resection constituted the study population. Those that manifested with metastatic disease revealed small liver metastases that during surgery were treated with a partial (Wedge/anatomic) liver resection.

Clinicopathological features
Clinicopathological data were identified from a prospectively collected database. A retrospective analysis followed in a non-stratified and non-matched manner. Annotation included patient age, gender, location, pT/pN classification, tumor grade, histologic subtype, vascular invasion, perineural invasion, the presence of metastasis and the clinical stage of the disease according to UICC (Union for International Cancer Control).

Immunohistochemistry
Standard procedures were used for the preparation of the formalin-fixed, paraffin-embedded tissue blocks. Staining was done on regular four µm sections of formalin-fixed and paraffin-embedded tumour tissue. Immunohistochemistry was performed on tissue sections with the standard biotinavidin technique using a monoclonal antibody against fascin-1. The expression of fascin-1 was analyzed by using the fascin-1 mouse monoclonal IgG 1 (kappa light chain) antibody (55K-2:sc-21743) purchased from Santa Cruz Biotechnology, Heidelberg, Germany.

Evaluation of immunohistochemistry
Histopathological evaluation was performed independently by two experienced pathologists in the field (A.N. and E.P.) and by blinding both pathologists to the clinical data of the patients.
Immunohistochemistry was applied in a three-step method (avidin-biotin-peroxidase) for determining fascin-1 expression in paraffin tissue-embedded sections of 111 CRC specimens as previously described 17-18 .
Expression of fascin-1 was semiquantitatively classified. Roc curve and X-tile were used to define cut off points and consequently, the levels of expression of fascin-1. More specifically, using ROC (Receiver Operating Characteristics) curve, a specimen exhibiting fascin-1 staining in less than 10% of the cancer cells was defined as a specimen with low expression of fascin-1. Nevertheless, using X-tile, two cut off points (10% and 35%) revealed significant data regarding survival. Therefore, patients displaying fascin-1 expression between 10%-35% were classified as patients with a moderate expression of fascin-1, whereas patients exhibiting within their specimens fascin-1 expression ≥ 35% were classified as patients with high fascin-1 expression. Staining was evaluated in the cytoplasmic membrane and cytoplasm of tumor cells. The intensity of staining was scored as follows: 0: no staining of the cells, 1: mild staining, 2: intermediate degree of staining, 3: strong staining intensity. A specimen was evaluated as positive for fascin-1 expression when moderate to high expression of the marker was present and exhibited strong staining intensity.

Outcomes
3-year PFS and 5-year OS were used as the primary outcomes of this study.

Baseline descriptive and tumor characteristics of the study population
A total of 111 patients with CRC underwent oncological surgical resection at the second department of Propedeutic Surgery, Laiko General Hospital, National and Kapodistrian University of Athens. The mean age of the study population was 70.9 years (range 42-90 years), and 61.3% were male patients. The primary tumor location was left-sided in 71.2%, with 38.7% representing rectal cancers and right-sided in 28.8% of the patients. The tumor had grown through the muscularis propria and into the subserosa (T3) in 53.2% of the patients. Regarding lymph node metastasis, 53.2% of the patients had no lymph node metastasis, 21.6% presented lymph node metastasis in 1-3 regional lymph nodes, and 25.2% to 4 or more regional lymph nodes. Metastatic disease in terms of resectable liver metastasis was present in 15  According to the cutoff points that were defined, 59.5% of the patients exhibited low expression of fascin-1, 26.1% moderate expression, and 14.4% high expression of fascin-1 (Table 1)

Discussion
The present study demonstrated that fascin-1 expression correlates with aggressive clinical features,

Conclusions
In the present study, fascin-1 positive patients displayed aggressive clinical features and demonstrated significantly poor 3-year progression-free survival as well as 5-year overall survival already in early-stage disease. Therefore, fascin-1 could represent a potential target for the development of a tumor profiling test in order to identify patients that are prone to disease recurrence manifested either as local relapse or metastasis. An issue that requires further investigation is whether fascin-1 positive CRC patients with early-stage disease would profit from adjuvant chemotherapy as the current indication is somewhat limited.     Kaplan Meier curve illustrating overall survival in months for patients with early stage cancer and low vs moderate and high expression of fascin-1