Prognostic values of proliferating cell nuclear antigen (PCNA) and Ki-67 for radiotherapy of oesophageal squamous cell carcinomas

A multi-omics study delineates new molecular features and therapeutic targets for esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a major histological subtype of esophageal cancer with inferior prognosis. Here, we conducted comprehensive transcriptomic, proteomic, phosphoproteomic, and metabolomic characterization of human, treatment-naive ESCC and paired normal adjacent tissues (cohort 1, n = 24) in an effort to identify new molecular vulnerabilities for ESCC and potential therapeutic targets. Integrative analysis revealed a small group of genes that were related to the active posttranscriptional and posttranslational regulation of ESCC. By using proteomic, phosphoproteomic, and metabolomic data, networks of ESCC-related signaling and metabolic pathways that were closely linked to cancer etiology were unraveled. Notably, integrative analysis of proteomic and phosphoproteomic data pinpointed that certain pathways involved in RNA transcription, processing, and metabolism were stimulated in ESCC. Importantly, proteins with close linkage to ESCC prognosis were identified. By enrolling an ESCC patient cohort 2 (n = 41), three top-ranked prognostic proteins X-prolyl aminopeptidase 3 (XPNPEP3), bromodomain PHD finger transcription factor (BPTF), and fibrillarin (FBL) were verified to have increased expression in ESCC. Among these prognostic proteins, only FBL, a well-known nucleolar methyltransferase, was essential for ESCC cell growth in vitro and in vivo. Furthermore, a validation study using an ESCC patient cohort 3 (n = 100) demonstrated that high FBL expression predicted unfavorable patient survival. Finally, common cancer/testis antigens and established cancer drivers and kinases, all of which could direct therapeutic decisions, were characterized. Collectively, our multi-omics analyses delineated new molecular features associated with ESCC pathobiology involving epigenetic, posttranscriptional, posttranslational, and metabolic characteristics, and unveiled new molecular vulnerabilities with therapeutic potential for ESCC.

The role of DNA damage response in chemo- and radio-resistance of cancer cells: Can DDR inhibitors sole the problem?

Up to now, many improvements have been made in providing more therapeutic strategies for cancer patients. The lack of susceptibility to common therapies like chemo- and radio-therapy is one of the reasons why we need more methods in the field of cancer therapy. DNA damage response (DDR) is a set of mechanisms which identifies DNA lesions and triggers the repair process for restoring DNA after causing an arrest in the cell cycle. The ability of DDR in maintaining the genome stability and integrity can be favorable to cancerous cells which are exposed to radiation therapy or are treated with chemotherapeutic agents. When DDR mechanisms are error-free in cancer cells, they can escape the expected cellular death and display resistance to treatment. In this regard, targeting different components of DDR can help to increase the susceptibility of advanced tumors to chemo- and radio-therapy.

Influence of XRCC4 expression in esophageal cancer cells on the response to radiotherapy

DNA double-strand break (DSB) is one of the most serious forms of damage induced by ionizing irradiation and is mainly repaired by the non-homologous end joining (NHEJ) repair. Immunohistochemical analysis of proteins involved in NHEJ, such as XRCC4 (X-ray repair cross-complementing protein 4), Ku86 and DNA-PKcs (DNA-dependent protein kinase, catalytic subunits), may be useful for predicting tumor radiosensitivity. We examined 92 patients with esophageal squamous cell carcinoma (ECSS) who were treated by radiotherapy between 1999 and 2008. Immunohistochemical examination of tumor tissue for Ki-67 and DSB-related proteins, including XRCC4, Ku86, and DNA-PKcs, was performed using pretreatment biopsy specimens. Low expression of XRCC4 was detected in 31 of 92 examined samples (33.7 %). The 5-year overall survival (OS) rate was 67.7 % in the low expression group and 31.0 % in the high expression group (P = 0.00). Multivariate analysis confirmed that advanced T-stage (HR 3.24, P = 0.01), radiation dose less than 66 Gy (HR 2.23, P = 0.02), absence of systemic chemotherapy (HR 2.59, P = 0.05), and high expression of XRCC4 (HR 12.0, P = 0.02) were independent prognostic factors for predicting poor OS. Other DSB-related proteins and Ki-67 were not predictive factors. XRCC4 expression might have an influence on results of radiotherapy for patients with ESCC.

Prognostic value of vascular endothelial growth factor expression in patients with esophageal cancer: a systematic review and meta-analysis

BACKGROUND

VEGF is a prime mediator of tumorigenesis and metastasis. Various studies assessing the prognostic value of VEGF in patients with esophageal cancer remain controversial. This study aims to comprehensively and quantitatively summarize the evidence on the suitability of VEGF to predict patients' survival.

METHODS

Searches were applied to PubMed and EMBASE until December 31, 2011, without language restrictions. Studies were assessed for quality using REMARK (Reporting recommendations for tumor MARKer prognostic studies). Data were collected comparing overall survival in patients with high VEGF level with those with low level. We conducted a systematic review of 31 studies (n = 2,387 patients) and completed a meta-analysis of 30 studies (n = 2,345 patients) that correlated VEGF levels with overall survival. Data were synthesized with HRs.

RESULTS

The estimated risk of death was 1.82-fold greater in patients with high VEGF expression [95% confidence interval (CI), 1.58-2.08]. The heterogeneity was not significant (P = 0.130) between studies. High VEGF expression was associated with worse survival in esophageal squamous cell carcinoma (HR, 1.81; 95% CI, 1.57-2.10) and there was no significance in between-study heterogeneity (P = 0.185). Data collected were not sufficient to determine the prognostic value of VEGF in patients with esophageal adenocarcinoma.

CONCLUSIONS

In this meta-analysis, elevated VEGF expression was associated with poor survival in patients with esophageal cancer but not esophageal adenocarcinoma.

IMPACT

These results support further investigation of VEGF expression for predicting poor survival in patients with esophageal carcinoma and may have implications for treatments directed at inhibiting VEGF-mediated angiogenesis.

Analysis and results of Ku and XRCC4 expression in hypopharyngeal cancer tissues treated with chemoradiotherapy

DNA double-strand break (DSB) is one of the most serious forms of damage induced by ionizing irradiation. Non-homologous end-joining (NHEJ) is a key mechanism of DNA DSB repair. The immunohistochemical analysis of proteins involved in NHEJ may have potential as a predictive assay for tumor radiosensitivity. We examined the correlation between the expression of proteins involved in DNA DSB in biopsy specimens and the results of chemoradiotherapy in hypopharyngeal cancers. Fifty-seven patients with previously untreated squamous cell carcinoma of the hypopharynx were treated between March 2002 and December 2009. Most patients (75%) had stage III or IV disease. The chemotherapy consisted of cisplatin plus 5FU or S-1. A tumor dose of 50 Gy was usually administered to the primary tumor and regional lymph nodes. Doses of 10-20 Gy were usually added to the primary tumor with reduced fields after 50 Gy. The 5-year disease-free survival rate was 100% for patients in stage I, 90% in stage II, 64% in stage III and 50% in stage IV. In stages I-III, patients with a lower expression of Ku70 or XRCC4 tended to have better locoregional control. These results indicated that a lower expression of Ku70 or XRCC4 may be correlated with higher radiosensitivity. Two patients had distant metastasis alone, of which one had 0% expression of Ku70 and the other had 0% expression of Ku86. The absence of Ku70 or Ku86 expression indicates low DNA-PK activity. Low DNA-PK activity due to a low expression of Ku may result in the genetic alteration of cancer cells, leading to a higher tendency of distant metastasis. This finding suggests that proteins involved in NHEJ may have an impact on the treatment results of chemoradiotherapy in hypopharyngeal cancer.

Expressão citofotométrica do marcador CD34 no carcinoma epidermóide de esôfago

RACIONAL: O câncer de esôfago está entre as seis neoplasias malignas mais comuns do mundo. Devido à sua grande agressividade clínica, o subtipo carcinoma epidermóide constitui um dos tumores de pior prognóstico, com alto índice de morbi-mortalidade. Marcadores de biologia molecular tem sido apontados como forte coadjuvante no diagnóstico e graduação de tumores. A angiogênese, evento essencial para a progressão tumoral, pode ser estudada pelo marcador CD34. OBJETIVO: Determinar por citofotometria, usando o sistema SAMBA 4000, a expressão do marcador CD34 no carcinoma epidermóide de esôfago e, correlacioná-los com dados clínico-patológicos (idade, sexo, grau de diferenciação do tumor, estadio, tamanho, localização, profundidade e acometimento de linfonodos). MÉTODOS: Avaliaram-se 29 amostras teciduais de carcinoma epidermóide de esôfago utilizando-se coloração imunoistoquímica com marcador anti-CD34. A quantificação da expressão deste marcador foi realizada por citometria de imagem, pelo sistema SAMBA 4000 nas variáveis índice de marcagem e densidade óptica. A correlação entre subgrupos e análise estatística dos resultados foi realizada com o programa SPSS. RESULTADOS: A expressão média do marcador CD34 foi de 73,40% + 15,20 no índice de marcagem e 56,10 + 23,54 na densidae óptica. O CD34 não apresenta correlação estatisticamente significativa com as características clínico-histopatológicas estudadas (idade, sexo, grau de diferenciação do tumor, estadio, tamanho, localização, profundidade e acometimento de linfonodos). CONCLUSÃO: O marcador CD34 apresenta expressão no carcinoma epidermóide de esôfago, com maior valor no índice de marcagem em relação à densidade óptica. Ele4 não apresenta correlação com as características clínico-histopatológicas estudadas.

Cell-cycle regulators and the Ki-67 labeling index can predict the response to chemoradiotherapy and the survival of patients with locally advanced squamous cell carcinoma of the esophagus

BACKGROUND

We investigated whether aberrant p53 and p16 expression, the Ki-67 labeling index (LI), and int-2/cyclin D1 gene amplification predict the response to chemoradiotherapy (CRT) in patients with locally advanced esophageal squamous cell carcinoma (ESCC).

METHODS

p53 and p16 expression status, the Ki-67 LI, and int-2/cyclin D1 amplification were assessed by immunohistochemical staining and slot blot analysis in pretreatment endoscopic biopsy specimens of 41 patients with T4 or M1 Lym (distant lymph node metastasis) ESCC. All patients received a course of chemotherapy (5-fluorouracil and cisplatin) with radiotherapy.

RESULTS

The CRT therapeutic response rate was 71%, and resection after CRT was successful in 15 of the cases in which the CRT effect was significant. The cumulative survival rate after CRT in the p53-negative patients was significantly higher than in the p53-positive patients (P =.037). The mean Ki-67 LI in the CRT response cases was significantly higher than in the CRT no-response cases (P =.023). Multivariate regression analysis revealed high Ki-67 LI to be an independent variable linked to a pathologic complete response to CRT (P =.033). The cumulative survival rate after CRT in the group that was p53-negative and int-2/cyclin D1 amplification-positive was significantly higher than in the other groups (P =.008).

CONCLUSIONS

Evaluating predictive factors in pretreatment endoscopic biopsy specimens may allow selection of more suitable multimodal treatment for ESCC patients and improve their quality of life.

Impact of neoadjuvant chemotherapy on Ki-67 and PCNA labeling indices for esophageal squamous cell carcinomas

PURPOSE

The effects of neoadjuvant chemotherapy (CT) on Ki-67 and proliferating cell nuclear antigen (PCNA) labeling index (LI) were analyzed, using biopsy and surgical specimens of esophageal cancer.

METHOD AND MATERIALS

Immunohistochemical staining for Ki-67 and PCNA was performed for biopsy and surgical specimens of 35 patients with esophageal squamous cell carcinoma. Seventeen patients were treated with neoadjuvant CT (CT group), while no preoperative treatment was performed for the remaining 18 patients (control group). As neoadjuvant CT, cisplatin of 50 mg/body/week was administered 2-5 times (100-250 mg in total) until 7-10 days before subtotal esophagectomy.

RESULT

Significant correlation between the LIs of biopsy and surgical specimens was observed for the control group (p = 0.006 for Ki-67 and p = 0.005 for PCNA), although both LIs of surgical specimens were significantly higher than those of biopsy specimens (p < 0.05). However, no significant correlation between LIs of biopsy specimens and those of surgical specimens was observed for the CT group. In addition, the LIs of the surgical specimens of the CT group were significantly lower than the LIs of the control group (p < 0.005 for Ki-67 and p < 0.05 for PCNA). Significant decrease in Ki-67 LI after neoadjuvant CT was noted especially for well or moderately differentiated squamous cell carcinomas and/or tumors treated with high-dose cisplatin (150-250 mg).

CONCLUSION

Significant correlation of Ki-67 and PCNA LIs between biopsy and surgical specimens was demonstrated for the control group. Neoadjuvant CT decreased the percentage of cycling and proliferative tumor cells of esophageal cancer.

Markers of proliferation in normal and leukoplakic oral epithelia

We have reviewed the recent literature on immunohistochemical markers of cell proliferation in normal oral epithelia and leukoplakias. Most findings, including our own, point to an increased proliferation in oral leukoplakias that correlates with the degree of dysplasia. Although the basal layer of normal oral epithelia showed a very low proliferative activity, oral leukoplakias, even those containing low-grade dysplasia, exhibited a very significant increase in proliferation. High-grade dysplasia could be clearly differentiated from both low-grade dysplasia and normal oral epithelia by the presence of proliferating cells in the superficial cell strata, i.e. above or superficial to the parabasal layer. These changes were detected with several markers including PCNA, Ki-67 (Mib-1), cyclin D1 and CENP-F as well as with procedures using pulse labeling with BrDU, IrDU and tritiated thymidine. Comparison of all methods showed more similarities than discrepancies. Nevertheless, because of its relative simplicity of use and universal acceptance in many other sites, Ki-67 (Mib-1) seems to be the most reliable immunohistochemical marker for future use in cancer prevention and therapeutic clinical trials.