Mitotic index and ki-67 nuclear antigen labeling index as predictors of chemotherapy response in uterine cervical carcinoma

Diffusion kurtosis MRI as a predictive biomarker of response to neoadjuvant chemotherapy in high grade serous ovarian cancer

This study assessed the feasibility of using diffusion kurtosis imaging (DKI) as a measure of tissue heterogeneity and proliferation to predict the response of high grade serous ovarian cancer (HGSOC) to neoadjuvant chemotherapy (NACT). Seventeen patients with HGSOC were imaged at 3 T and had biopsy samples taken prior to any treatment. The patients were divided into two groups: responders and non-responders based on Response Evaluation Criteria In Solid Tumours (RECIST) criteria. The following imaging metrics were calculated: apparent diffusion coefficient (ADC), apparent diffusion (Dapp) and apparent kurtosis (Kapp). Tumour cellularity and proliferation were quantified using histology and Ki-67 immunohistochemistry. Mean Kapp before therapy was higher in responders compared to non-responders: 0.69 ± 0.13 versus 0.51 ± 0.11 respectively, P = 0.02. Tumour cellularity correlated positively with Kapp (rho = 0.50, P = 0.04) and negatively with both ADC (rho = -0.72, P = 0.001) and Dapp (rho = -0.80, P < 0.001). Ki-67 expression correlated with Kapp (rho = 0.53, P = 0.03) but not with ADC or Dapp. In conclusion, Kapp was found to be a potential predictive biomarker of NACT response in HGSOC, which suggests that DKI is a promising clinical tool for use oncology and radiology that should be evaluated further in future larger studies.

The influence of tumour microenvironmental factors on the efficacy of cisplatin and novel platinum(IV) complexes

The chemotherapeutic drug cisplatin is an important treatment for many types of solid tumours, in particular non-small cell lung cancer (NSCLC). Platinum(IV) complexes offer several advantages to cisplatin due to their requirement for reduction to the active platinum(II) form to elicit cytotoxicity. This should minimise non-specific effects and facilitate higher amounts of the active complexes reaching the target DNA. Hypoxia and a quiescent cell population are features of the tumour microenvironment known to lead to resistance to many chemotherapeutic agents. It is unclear how these microenvironmental factors will impact on the efficacy of novel platinum(IV) complexes. Consequently, the cytotoxicities of several platinum drugs were determined in monolayer and tumour spheroid cultures derived from NSCLC lines. Platinum(IV) reduction potential correlated well with cytotoxicity. The complex containing a chloro axial ligand demonstrated the greatest potency and the drug with the hydroxy ligand was the least effective. Although drug cytotoxicity was not enhanced under hypoxic conditions, both cisplatin and the platinum(IV) complexes retained full potency. In addition, all of the platinum drugs retained the ability to evoke apoptosis in quiescent cells. In summary, unlike many anticancer drugs, the platinum(IV) complexes retain cytotoxic potency under resistance-inducing tumour microenvironmental conditions and warrant further investigation as more selective alternatives to current platinum-based therapy for the treatment of solid tumours.

A model of quiescent tumour microregions for evaluating multicellular resistance to chemotherapeutic drugs

The quiescent cell population of tumours poses a barrier to the success of many cancer therapies. Most chemotherapeutic drugs target proliferating cells, but the growth fraction of many tumours is low. Based on the multicellular tumour spheroid model, a system was developed using human colon adenocarcinoma (DLD-1) cells to mimic the microenvironment of quiescent microregions of solid tumours. The quiescent tumour spheroids (TS(Q)) showed decreased expression of the proliferation marker Ki-67 and increased expression of the quiescence marker p27(kip1) compared to proliferating spheroids (TS(P)). The quiescent status of the TS(Q) was confirmed by long-term growth assessment. The quiescence was completely reversible demonstrating that the TS(Q) retained the ability to proliferate and morphological assessment by light microscopy confirmed the absence of significant apoptosis. When the efficacy of widely used chemotherapeutic drugs was determined, vinblastine, doxorubicin, cisplatin and 5-fluorouracil (5-FU) all produced significant cell death in the TS(P). However, while still effective, the potencies of doxorubicin and cisplatin were significantly reduced in TS(Q). In contrast, 5-FU and vinblastine did not produce cell death in the TS(Q). In summary, TS(Q) show considerable resistance to a panel of established chemotherapeutic agents and represent a useful model for evaluating the efficacy of drugs and other cancer therapies in quiescent tumours.

Pre-treatment mitotic index versus computer-quantitated Ki-67 nuclear antigen labeling index as predictors of response to neoadjuvant chemotherapy in uterine cervical carcinoma

In order to evaluate the usefulness of the mitotic index (MI) and the Ki-67 nuclear antigen labeling index (Ki67LI) in pre-treatment biopsy specimens as predictors of response to chemotherapy for uterine cervical carcinomas, twelve patients with squamous cell carcinoma who received neoadjuvant chemotherapy before radical surgery were investigated. The MI and computer-quantitated Ki67LI were determined using H&E and immunostained slides of biopsy specimens collected before chemotherapy. Tumor size was measured three-dimensionally by MR imaging, and assessed before and after chemotherapy. We compared the values of MI and Ki67LI with changes in tumor size and the following results were obtained. 1) The percentage reduction in tumor size ranged from 0 to 98%. The MI ranged from 0.5 to 15, and Ki67LI ranged from 0.01 to 50.1%. 2) A significant positive correlation was observed between response to chemotherapy assessed on MR image and MI [Spearman's correlation coefficient (r) =0.66, n=12, p=0.027], and between response to chemotherapy and Ki67LI (r=0.72, n=12, p=0.017). 3) A significant correlation was observed between MI and computer-assessed Ki67 LI [Pearson's correlation coefficient (r) =0.80, n=12, p=0.002]. Therefore, pre-chemotherapy MI and Ki67LI were both good predictors of response to platinum-based chemotherapy. Because MI is technically more convenient and economically less expensive than computer-quantitated Ki67LI, MI remains a simple and reliable predictor from the clinical point of view.