Markers of Cell Cycle-Mediated Drug Resistance And Prognosis Of Patients Receiving Preoperative Combined Modality Therapy For Rectal Cancer

Extracellular Vesicle-Mediated Chemoresistance in Oral Squamous Cell Carcinoma

Oral Squamous Cell Carcinoma (OSCC) remains a cancer with poor prognosis and high recurrence rate. Even with multimodal treatment options available for OSCC, tumor drug resistance is still a persistent problem, leading to increased tumor invasiveness among OSCC patients. An emerging trend of thought proposes that extracellular vesicles (EVs) play a role in facilitating tumor progression and chemoresistance via signaling between tumor cells. In particular, exosomes and microvesicles are heavily implicated in this process by various studies. Where primary studies into a particular EV-mediated chemoresistance mechanism in OSCC are limited, similar studies on other cancer cell types will be used in the discussion below to provide ideas for a new line of investigation into OSCC chemoresistance. By understanding how EVs are or may be involved in OSCC chemoresistance, novel targeted therapies such as EV inhibition may be an effective alternative to current treatment options in the near future. In this review, the current understandings on OSCC drug mechanisms under the novel context of exosomes and microvesicles were reviewed, including shuttling of miRNA content, drug efflux, alteration of vesicular pH, anti-apoptotic signaling, modulation of DNA damage repair, immunomodulation, epithelial-to-mesenchymal transition and maintenance of tumor by cancer stem cells.

p53 and p27 as predictors of clinical outcome for rectal-cancer patients receiving neoadjuvant therapy

Our aim was to examine whether certain molecular markers, specifically p53, p21, p27, and Bcl-2, could be used to predict the tumor response of rectal cancer to neoadjuvant therapy and determine the overall and disease-free survival rates of patients following neoadjuvant therapy. Seventy-seven patients with rectal cancers were used in this study. All of them received neoadjuvant therapy and 53 of them were given radical surgery. Immunohistochemical tests were performed for the four markers mentioned above using biopsy specimens obtained from 70 of the patients prior to radiation. The identical tests were performed for the same markers using excised specimens from the patients after radical surgery. For the pre-radiation specimens, the positive rate for having p27 and Bcl-2 markers was 32.7% and 16.6%, respectively. This rate increased to 73.5% and 41.6% (p=0.001 and 0.012, respectively) in the specimens obtained after the surgery. With respect to "fair response (FR)" of patients, the pre-radiation biopsy specimens showed significant difference for the p53 (-) and p27 (+) markers (p=0.006). Patients with a 3-year overall survival rate were found to have, from their surgical specimens, 92% of the p27 (+) and 75% of p27 (-) markers (p=0.0058). Our study showed: first, the rate of positive identification of molecular markers, p27 and Bcl-2, increased following neoadjuvant therapy. Second, either the p53 (-) or p27 (+) status was a good predictor for FR in the pre-radiation biopsy specimens. Third, patients with p27 (+) markers in the surgical specimens lived longer at 3 years.