The role of double-strand break repair, translesion synthesis, and interstrand crosslinks in colorectal cancer progression-clinicopathological data and survival

BACKGROUND AND OBJECTIVES

DNA repair is a new and important pathway that explains colorectal carcinogenesis. This study will evaluate the prognostic value of molecular modulation of double-strand break repair (XRCC2 and XRCC5); DNA damage tolerance/translesion synthesis (POLH, POLK, and POLQ), and interstrand crosslink repair (DCLRE1A) in sporadic colorectal cancer (CRC).

METHODS

Tumor specimens and matched healthy mucosal tissues from 47 patients with CRC who underwent surgery were assessed for gene expression of XRCC2, XRCC5, POLH, POLK, POLQ, and DCLRE1A; protein expression of Polk, Ku80, p53, Ki67, and mismatch repair MLH1 and MSH2 components; CpG island promoter methylation of XRCC5, POLH, POLK, POLQ, and DCLRE1A was performed.

RESULTS

Neoplastic tissues exhibited induction of POLK (P < .001) and DCLRE1A (P < .001) expression and low expression of POLH (P < .001) and POLQ (P < .001) in comparison to healthy paired mucosa. Low expression of POLH was associated with mucinous histology and T1-T2 tumors (P = .038); low tumor expression of POLK was associated with distant metastases (P = .042). CRC harboring POLK promoter methylation exhibited better disease-free survival (DFS) (P = .005).

CONCLUSIONS

This study demonstrated that low expression or unmethylated POLH and POLK were related to worse biological behavior tumors. However, POLK methylation was associated with better DFS. POLK and POLH are potential prognostic biomarkers in CRC.

Brazilian consensus on the diagnosis and treatment of extremities soft tissue sarcomas

INTRODUCTION

Soft tissue sarcomas (STSs) are rare tumors and constitute only 1% of all tumors in adults. Indeed, due to their rarity, most cases in Brazil are not treated according to primary international guidelines.

METHODS

This consensus addresses the treatment of STSs in the extremities. It was made by workgroups from Brazilian Societies of Surgical Oncology, Orthopaedics, Clinical Oncology, Pathology, Radiology and Diagnostic Imaging, and Radiation Oncology. The workgroups based their arguments on the best level of evidence in the literature and recommendations were made according to diagnosis, staging, and treatment of STSs. A meeting was held with all the invited experts and the topics were presented individually with the definition of the degree of recommendation, based on the levels of evidence in the literature.

RESULTS

Risk factors and epidemiology were described as well as the pathological aspects and imaging. All recommendations are described with the degree of recommendation and levels of evidence.

CONCLUSION

Recommendations based on the best literature regional aspects were made to guide professionals who treat STS. Separate consensus on specific treatments for retroperitoneal, visceral, trunk, head and neck sarcomas, and gastrointestinal stromal tumor, are not contemplated into this consensus.

Guidelines of the Brazilian Society of Oncologic Surgery for pelvic exenteration in the treatment of cervical cancer

BACKGROUND AND OBJECTIVES

The primary treatment for locally advanced cases of cervical cancer is chemoradiation followed by high-dose brachytherapy. When this treatment fails, pelvic exenteration (PE) is an option in some cases. This study aimed to develop recommendations for the best management of patients with cervical cancer undergoing salvage PE.

METHODS

A questionnaire was administered to all members of the Brazilian Society of Surgical Oncology. Of them, 68 surgeons participated in the study and were divided into 10 working groups. A literature review of studies retrieved from the National Library of Medicine database was carried out on topics chosen by the participants. These topics were indications for curative and palliative PE, preoperative and intraoperative evaluation of tumor resectability, access routes and surgical techniques, PE classification, urinary, vaginal, intestinal, and pelvic floor reconstructions, and postoperative follow-up. To define the level of evidence and strength of each recommendation, an adapted version of the Infectious Diseases Society of America Health Service rating system was used.

RESULTS

Most conducts and management strategies reviewed were strongly recommended by the participants.

CONCLUSIONS

Guidelines outlining strategies for PE in the treatment of persistent or relapsed cervical cancer were developed and are based on the best evidence available in the literature.

Clinical importance of DNA repair in sporadic colorectal cancer

Colorectal cancer (CRC) is the third major cause of cancer-related deaths worldwide. However, despite the scientific efforts to provide a molecular classification to improve CRC clinical practice management, prognosis and therapeutic decision are still strongly dependent on the TNM staging system. Mismatch repair system deficiencies can occur in many organs, but it is mainly a hallmark of CRC influencing clinical outcomes and response to therapy. This review will discuss the effect of the modulation of other DNA repair pathways (direct, excision and double strand break repairs) in the clinical and pathological aspects of colorectal cancer and its potential as prognostic and predictive biomarkers.