Detection of B7-H4 and p53 in pancreatic cancer: potential role as a cytological diagnostic adjunct

Evaluation of apoptosis in cytologic specimens

A hallmark of neoplasia is dysregulated apoptosis, programmed cell death. Apoptosis is crucial for normal tissue homeostasis. Dysregulation of apoptotic pathways leads to reduced cytocidal responses to chemotherapeutic drugs or radiation and is a frequent contributor to therapeutic resistance in cancer. The literature pertaining to detection of apoptotic pathway constituents in cytologic specimens is reviewed herein. Virtually all methods for detecting apoptosis, including classic cytomorphologic evaluation, TUNEL assay, immunocytochemistry, and gene sequence analysis, may be applied to cytologic samples as well as tissue. Components of both intrinsic and extrinsic apoptotic pathways have been studied, including many reports examining p53 and bcl-2, as well as studies of caspase inhibitory proteins XIAP and survivin, death receptors and ligands such as Fas, Fas-ligand, and TRAIL. p53 undergoes oncogenic alteration more than any other protein; its immunocytochemical detection almost always connotes loss of its physiologic role as an inducer of apoptosis in response to a damaged genome. Several reports establish cytologic sampling as being as useful as tissue sampling. In one respect cytologic sampling is superior to tissue sampling in particular, by allowing clinicians to repeat sampling of the same tumor before and after administration of therapy; a number of reports use this approach to attempt to predict tumor response by assaying the effect of chemotherapy on the induction of apoptosis.

Expression of B7-H4 in blood of patients with gastric cancer predicts tumor progression and prognosis

BACKGROUND AND OBJECTIVES

B7-H4 is a novel molecular B7 ligand that plays an important role as a negative regulator of the T cell-mediated immune response. However, the clinical significance of B7-H4 expression in gastric cancer remains uncertain. Here, we assessed B7-H4 expression in blood of patients with gastric cancer to determine whether or not it can predict tumor progression and prognosis.

METHODS

We measured B7-H4 mRNA expression by quantitative RT-PCR in five gastric cell lines as well as in blood specimens from 94 patients with gastric cancer and from 22 healthy volunteers.

RESULTS

Significantly more B7-H4 mRNA copies were found in gastric cell lines and in blood from patients with gastric cancer than in blood from healthy volunteers (P < 0.0001 and P < 0.0001, respectively). B7-H4 expressed in 71 (75.5%) of 94 patients with gastric cancer significantly correlated with depth of tumor invasion, lymph node metastasis, and overall stage (P = 0.006, P = 0.001, and P < 0.001, respectively). The 5-year survival rate was significantly lower in patients with than without B7-H4 expression (P = 0.04).

CONCLUSIONS

The evaluation of B7-H4 expression in blood is a useful tool for predicting the progression of gastric cancer and prognosis.

B7-H4 expression promotes tumorigenesis in ovarian cancer

INTRODUCTION

It has been previously shown that B7-H4, one of the B7 family members that serve as negative regulators of T cell function, has altered expression levels in a variety of cancers, overexpression of B7-H4 promotes cellular transformation. However, there is still lack of adequate evidence to establish a direct connection between B7-H4 expression and malignant transformation.

METHODS

Herein, we constructed pE-green fluorescent protein-N1/B7-H4 mammalian expression vector and transfected into B7-H4-negative human ovarian cancer cell line SKOV3. Cellular proliferation, apoptosis, adhesion, motility, and invasion were examined in vitro. Cells injected subcutaneously into severe combined immunodeficient mouse were analyzed for the possible functions of B7-H4 in ovarian tumorigenesis in vivo.

RESULTS

Fluorescence microscopy studies confirmed that the B7-H4-green fluorescent protein localizes in the cytoplasm of SKOV3/B7-H4 cells, whereas green fluorescent protein is uniformly distributed throughout the cell. B7-H4 promoted cellular proliferation rate and increased cell adhesion, migration, and invasion. In addition, SKOV3 cells expressing B7-H4 gained growth advantage in the xenograft model in vivo.

CONCLUSIONS

These studies demonstrate that B7-H4 directly promotes malignant transformation of ovarian cancer cell line, and provides a potential therapeutic strategy for targeting B7-H4 to inhibit progression of human ovarian cancers.

Controversies in the management of borderline resectable proximal pancreatic adenocarcinoma with vascular involvement

Synchronous major vessel resection during pancreaticoduodenectomy (PD) for borderline resectable pancreatic adenocarcinoma remains controversial. In the 1970s, regional pancreatectomy advocated by Fortner was associated with unacceptably high morbidity and mortality rates, with no impact on long-term survival. With the establishment of a multidisciplinary approach, improvements in preoperative staging techniques, surgical expertise, and perioperative care reduced mortality rates and improved 5-year-survival rates are now achieved following resection in high-volume centres. Perioperative morbidity and mortality following PD with portal vein resection are comparable to standard PD, with reported 5-year-survival rates of up to 17%. Segmental resection and reconstruction of the common hepatic artery/proper hepatic artery (CHA/PHA) can be performed to achieve an R0 resection in selected patients with limited involvement of the CHA/PHA at the origin of the gastroduodenal artery (GDA). PD with concomitant major vessel resection for borderline resectable tumours should be performed when a margin-negative resection is anticipated at high-volume centres with expertise in complex pancreatic surgery. Where an incomplete (R1 or R2) resection is likely neoadjuvant treatment with systemic chemotherapy followed by chemoradiation as part of a clinical trial should be offered to all patients.

The complex role of B7 molecules in tumor immunology

T-cell activation requires the interaction of the T-cell receptor with a cognate major histocompatibility complex (MHC)-peptide complex. Initiated by antigen engagement, the adaptive immune response is orchestrated by a complex balance between stimulatory and inhibitory signals that are predominantly controlled by members of the B7 family. Here, we review the current knowledge on B7 family members concerning their constitutive and regulated expression, modulation of the immune response and their role in the evasion of host immune surveillance. We also discuss recent therapeutic strategies that aim to improve immune-cell recognition of tumors and induce tolerance to autoreactive immune responses in normal tissues by manipulating B7 functions.