Focal adhesion kinase: predictor of tumour response and risk factor for recurrence after neoadjuvant chemoradiation in rectal cancer.

Rectal cancer represents about 30% of colorectal cancers, being around 50% locally advanced at presentation. Chemoradiation (CRT) followed by total mesorectal excision is the standard of care for these locally advanced stages. However, it is not free of adverse effects and toxicity and the complete pathologic response rate is between 10% and 30%. This makes it extremely important to define factors that can predict response to this therapy. Focal adhesion kinase (FAK) expression has been correlated with worse prognosis in several tumours and its possible involvement in cancer radio- and chemosensitivity has been suggested; however, its role in rectal cancer has not been analysed yet. To analyse the association of FAK expression with tumour response to CRT in locally advanced rectal cancer. This study includes 73 patients with locally advanced rectal cancer receiving standard neoadjuvant CRT followed by total mesorectal excision. Focal adhesion kinase protein levels were immunohistochemically analysed in the pre-treatment biopsies of these patients and correlated with tumour response to CRT and patients survival. Low FAK expression was significantly correlated with local and distant recurrence (P = 0.013). Low FAK expression was found to be a predictive marker of tumour response to neoadjuvant therapy (P = 0.007) and patients whose tumours did not express FAK showed a strong association with lower disease-free survival (P = 0.01). Focal adhesion kinase expression predicts neoadjuvant CRT response in rectal cancer patients and it is a clinically relevant risk factor for local and distant recurrence.

Predictive value of vrk 1 and 2 for rectal adenocarcinoma response to neoadjuvant chemoradiation therapy: a retrospective observational cohort study.

BACKGROUND: Neoadjuvant chemoradiotherapy (NACRT) followed by surgical resection is the standard therapy for locally advanced rectal cancer. However, tumor response following NACRT varies, ranging from pathologic complete response to disease progression. We evaluated the kinases VRK1 and VRK2, which are known to play multiple roles in cellular proliferation, cell cycle regulation, and carcinogenesis, and as such are potential predictors of tumor response and may aid in identifying patients who could benefit from NACRT. METHODS: Sixty-seven pretreatment biopsies were examined for VRK1 and VRK2 expression using tissue microarrays. VRK1 and VRK2 Histoscores were combined by linear addition, resulting in a new variable designated as "composite score", and the statistical significance of this variable was assessed by univariate and multivariate logistic regression. The Hosmer-Lemeshow goodness-of-fit test and area under the ROC curve (AUC) analysis were carried out to evaluate calibration and discrimination, respectively. A nomogram was also developed. RESULTS: Univariate logistic regression showed that tumor size as well as composite score were statistically significant. Both variables remained significant in the multivariate analysis, obtaining an OR for tumor size of 0.65 (95 % CI, 0.45-0.94; p = 0.021) and composite score of 1.24 (95 % CI, 1.07-1.48; p = 0.005). Hosmer-Lemeshow test showed an adequate model calibration (p = 0.630) and good discrimination was also achieved, AUC 0.79 (95 % CI, 0.68-0.90). CONCLUSIONS: This study provides novel data on the role of VRK1 and VRK2 in predicting tumor response to NACRT, and we propose a model with high predictive ability which could have a substantial impact on clinical management of locally advanced rectal cancer.

Decreased PLK1 expression denotes therapy resistance and unfavourable disease-free survival in rectal cancer patients receiving neoadjuvant chemoradiotherapy.

AIM: Polo-like kinase 1 (Plk1) plays a key role in mitotic cell division and DNA damage repair. It has been observed that either up-regulated or down-regulated Plk1 could induce mitotic defects that results in aneuploidy and tumorigenesis, probably depending on the context. Few previous reports have associated Plk1 expression with prognosis and response to radiotherapy in rectal carcinomas. The aim of this study is to investigate the prognostic impact of Plk1 expression and its role in predicting response to neoadjuvant cheomoradiotherapy in rectal cancer. METHODS AND RESULTS: Immunohistochemical analysis of Plk1 expression was performed in the pre-treatment tumour specimens from 75 rectal cancer patients. We analysed the assocation between Plk1 expression and clinicopathological parameters, pathologic response and outcome. Opposed to previous reports on this issue, low expression of Plk1 was significantly associated with a high grade of differentiation (P=0.0007) and higher rate of distant metastasis (P=0.014). More importantly, decreased levels of Plk1 were associated with absence of response after neoadjuvant therapy (P=0.049). Moreover, low Plk1 expression emerged as an unfavourable prognostic factor for disease-free survival in the non-responder group of patients (P=0.037). CONCLUSIONS: Decreased Plk1 expression was associated with poor pathologic response and worse disease-free survival in rectal cancer patients receiving neoadjuvant chemoradiotherapy, suggesting Plk1 as a clinically relevant marker to predict chemoradiotherapy response and outcome.