Preoperative neutrophil-to-lymphocyte ratio predicts the surgical outcome of Xp11.2 translocation/TFE3 renal cell carcinoma patients

Background The preoperative neutrophil-to-lymphocyte ratio (NLR), C-reactive protein/albumin ratio (CRP/Alb ratio) and platelet-to-lymphocyte ratio (PLR) have been demonstrated to predict the clinical outcome of various human cancer, including renal cell carcinoma(RCC). The aim of our study was to explore the prognostic values of these ratios in patients with Xp11.2 translocation/TFE3 gene fusions renal cell carcinoma (Xp11.2 tRCC). Methods A retrospective multicentre study was performed in 82 Xp11.2 tRCC patients who underwent radical or partial nephrectomy. The optimal cutoff values of the NLR, CRP/Alb ratio and PLR were determined by the receiver operating characteristic (ROC) analysis. The impact of the NLR, CRP/Alb ratio and PLR, as well as other clinicopathological characteristics, on disease-free survival (DFS) and overall survival (OS) were evaluated using the univariate and multivariate Cox regression analyses. Results The optimal cutoff values of the NLR, CRP/Alb ratio and PLR were set at 2.45, 140 and 0.08, respectively, according to the ROC analysis. Univariate analyses showed that the NLR, CRP/Alb ratio and PLR all were associated with DFS of Xp11.2 tRCC patients (P < 0.001, P = 0.005 and P = 0.001, respectively) and OS of Xp11.2 tRCC patients (P = 0.016, P = 0.003 and P = 0.014, respectively). Multivariate analysis indicated that the NLR was independently associated with DFS of Xp11.2 tRCC patients (hazard ratio [HR]: 4.25; 95% confidence interval [95% CI]: 1.19–15.18; P = 0.026) along with age (P = 0.004), the pT status (P < 0.001) and the pN status (P < 0.019), and the NLR (HR: 26.26; 95% CI: 1.44–480.3; P = 0.028) also was independently associated with OS in patients with Xp11.2 tRCC, along with age (P = 0.016) and a tumour thrombus (P = 0.007). Conclusion Overall, relatively high NLRs, CRP/Alb ratios and PLRs were associated with a poor prognosis of Xp11.2 tRCC patients; among of them, only the NLR independently predicted the progression of Xp11.2 tRCC, and the NLR may help to identify patients with high metastasis or relapse risk.


Background
Xp11.2 translocation/TFE3 gene fusions renal cell carcinoma (Xp11.2 tRCC) was first listed as a new type of renal cell carcinoma (RCC) in the 2004 by the World Health Organization (WHO). Since then, it has received wide attention [1][2][3][4][5]. Xp11.2 tRCC is characterized by various translocations of the transcription factor E3(TFE3) on chromosome Xp11.2, resulting in overexpression of the TFE3 protein [6]. Xp11.2 tRCC is a kind of relatively rare tumour that predominantly occurs in children and young adults [7]. Regardless of its low incidence, Xp11.2 RCC is more aggressive than conventional RCC because most adult present at advanced stages and invasive clinical courses [3,4]. Therefore, it is crucial to identify new preoperative prognostic factors to provide additional prognostic information for Xp11.2 tRCC patients. In addition, in regard to the risk of disease recurrence, is important to obtain prognostic information in the preoperative phase for the postoperative surveillance and possible adjuvant therapy.
To our knowledge, the prognostic value of inflammatory markers has never been investigated in the Xp11.2 tRCC patients. Additionally, compared with conventional RCC, Xp11.2 tRCC involves different genetic characteristics and biological pathways and is associated with a more worse prognosis [3,5,18]. In addition, inflammatory markers are more easily accessible than other prognostic factors before surgery. Therefore, there is a need to identify new preoperative prognostic markers to predict the clinical outcomes of surgical Xp11.2 tRCC patients. The aims of the present study were to examine the prognostic values of the NLR, CRP/Alb ratio and PLR in patients with Xp11.2 tRCC.

Patients
Institutional review board approval was obtained at Nanjing Drum Tower Hospital, Jiangsu Province Hospital, Jiangsu Cancer Hospital and Zhongda Hospital Southeast University for this multicentre retrospective study. All the patients have provided informed written consents to have their medical record data used in research. Between January 2007 and July 2017, 89 consecutive patients from the 4 Fig. 1 The predictive abilities of the preoperative NLR, CRP/Alb ratio and PLR were compared using ROC curves institutions described above who were diagnosed with Xp11.2 tRCC after radical or partial nephrectomy for a renal mass were reviewed for the present study. All clinicopathological data were retrieved from medical records from the department of urology as well as from pathology reports from the Institute of Pathology at each institution. The inclusion criteria included the following: 1) patients who were histologically and immunohistochemically (using the TFE3 protein nuclear stain) diagnosed with Xp11.2 tRCC; 2) the data on complete blood laboratory tests included the serum neutrophil count(NC), lymphocyte count(LC), platelet count (PLT), C-reactive protein (CRP) level and albumin (Alb) level within one week before performing radical or partial nephrectomy; and (3) patients without blood laboratory tests before surgery, patients with active inflammatory disease and patients with other tumours were excluded from the study. Finally, a total of 82 patients were enrolled in this study.

Clinical and pathological evaluation
The baseline clinical characteristics and pathologic information, including data on the age at the time of surgery, gender, tumour location, tumour size, symptoms at presentation, surgical treatment, pathological features, immunohistochemistry results, NC, LC, PLT, CRP level, Alb level, lactate dehydrogenase (LDH) level, urine protein, tumour stage, and nuclear grade, were all collected. Tumour stage was determined according to the seventh edition of the TNM-UICC/AJCC classification system, and the nuclear grade was defined based on the Fuhrman Grading System. The NLR was defined as the ratio of the NC to LC. The PLR was defined as the ratio of the PLT to LC. The CRP/Alb ratio was defined as the ratio of the serum CRP level to the serum albumin (Alb) level. Elevated LDH was defined as serum LDH > 245 U/L. The association between inflammatory parameters (LN, NC, PLT, CRP, NLR, PLR, CRP/Alb) and DFS was explored, and the ROC curves of the NLR, CRP/Alb ratio and PLR are shown in Fig. 1.

Patients follow-up
All patients enrolled in this study were followed-up every 3 months during the first 2 years, every 6 months for 3-5 years and every 12 months after 5 years until July 2017 or until death. A physical examination, laboratory tests, and dynamic computed tomography were performed at every visit. Overall survival (OS) was defined as the time interval between the date of surgery and the date of death or the last follow-up. Disease-free survival (DFS) was defined as the time interval between the date of surgery and date of disease recurrence or metastasis or the last follow-up in localized Xp11.2 tRCC patients who underwent radical or partial nephrectomy.

Statistical analyses
Statistical analyses were performed using SPSS version 24.0 software (SPSS, Chicago, IL, USA). The descriptive data (i.e., tumour size) were presented as the means ± standard deviation or medians, and Student's t-test was used for these variables. A comparison between groups was performed using the Chi-squared test. Receiver operating characteristic (ROC) analysis was used for the selection of effective inflammatory parameters and corresponding optimal cut-off values, and the area under the curve (AUC), sensitivity, specificity and P value

Patient and tumour characteristics
The clinicopathological characteristics of 82 Xp11.2 tRCC patients are shown in Table 1

Association of the preoperative NLR and clinicopathological characteristics
Stratified by the cut-off value, the association between the preoperative NLR and clinicopathological characteristics is summarized in Table 2. An elevated NLR was significantly associated with the tumour size (P < 0.001), Fuhrman-grade (P = 0.011), TNM stage (P < 0.001), pT status (P = 0.001), pN status (P < 0.001), tumour thrombus

Discussion
In this multicentre retrospective study, we investigated the prognostic values of the NLR, CRP/Alb ratio, and PLR in 82 Xp11.2 tRCC patients who underwent radical or partial nephrectomy. The results demonstrated that the NLR, CRP/Alb ratio and PLR were all significant predictors and that the NLR was an independent prognostic marker for patients with Xp11.2 tRCC. Increasing evidence has revealed the involvement of systemic inflammation in cancer development and progression. Neutrophils were shown to produce pro-angiogenic factors such as vascular endothelial growth factor to stimulate tumour development and progression [19]. Moreover, the cytokines involved in cancer-related inflammation, IL-6 and TNFα, may induce neutrophilia [20,21]. Additionally, relative lymphocytopenia may reflect a lower count of CD4+ T-helper lymphocytes, resulting in a suboptimal lymphocyte-mediated immune response to malignancy [22]. Therefore, an NLR may reflect the combined prognostic information of these two inflammatory factors, and a high NLR has been validated as a poor prognostic factor for several different human cancers [10], including clear cell RCC and non-clear cell RCC [14,17,[22][23][24]. C-reactive protein (CRP) is a prototype acute phase protein that was demonstrated to be produced in hepatocytes and regulated by growth factors in the malignant tumors such as IL-6 [25]. An elevated CRP level was reported to be associated with a poorer prognosis in various types of human cancers [25][26][27]. A study conducted by Guo et al. [16] summarized the potential mechanisms regarding how CRP is associated with cancer in follow several aspects:(1). An increased CRP level is created by the tissue inflammation, which is caused by the tumour growth; (2). Tumour antigens activate the immune responses, leading to increased CRP level; (3). Tumour cells increase CRP expression by producing inflammatory proteins, including CRP or by enhancing the role of inflammatory cytokines such as IL-6 and IL-8, which could indirectly increase the CRP level. More recently, several publications demonstrated that the CRP/Alb ratio could be used to predict the prognosis of several cancers [11,28,29], and two additional studies confirmed the prognostic value of the CRP/Alb ratio in RCC patients [16,30].
Since the possible association between an increased platelet level and cancer metastasis was first described in 1968 [31], an increased PLT level was confirmed to be a prognostic marker for several cancers, including RCC [32,33]. Furthermore, Emerging evidence has shown that the platelet-to-lymphocyte ratio (PLR) can be used to assess the response to systemic inflammation and RCC prognosis [12,15,16].
In this study, we explored the relationships of the NLR, CRP/Alb ratio and PLR with survival in Xp11.2 tRCC patients. Compared with the other systemic inflammatory markers, the NLR, CRP/Alb ratio and PLR had better predictive value for DFS (Fig. 1, Tables 2 and 3). Among of them, the NLR had the highest AUC value (P = 0.001). The optimal cut-off value of the NLR was 2.45, which is little lower than the cut-off values of two other studies,  [14,24]. We consider these differences to be due to the small size of our patients and uniqueness of this tumour. Regarding the CRP/Alb ratio and PLR, the optimal cut-off values were 0.083 and 140, respectively, similar to those reported in previous studies on RCC [15,16]. Univariate analyses for both DFS and OS showed that a higher NLR, CRP/Alb ratio and PLR were all associated with a poorer prognosis of Xp11.2 tRCC patients (Tables 4 and 5 Our findings demonstrate that the NLR, CRP/Alb ratio and PLR were all associated with a poor prognosis in Xp11.2 tRCC patients. Among them, only the NLR independently predicted surgical outcomes of Xp11.2 tRCC patients. These results are important for clinicians to make clinical decisions. According to these preoperative inflammatory markers, patients at high risk can be selected for further treatment and management. With these prognostic factors, more suitable preoperative therapies and more frequent follow-up strategies can be considered for certain high-risk patients with Xp11.2 tRCC.
In addition, the prognostic value of inflammatory markers has never been reported with Xp11.2 tRCC patients. We may, for the first time, predict the surgical outcomes of Xp11.2 tRCC patients using the NLR, CRP/Alb ratio and PLR. Moreover, the sample size of this study was the largest among studies of this tumour worldwide.
To the best of our knowledge, this is the first study that focused on the prognostic values of the NLR, CRP/Alb ratio and PLR in patients with Xp11.2 tRCC. However, this study possesses several limitations. First, our study is a retrospective study, which may limit the prognostic values of the NLR, CRP/Alb ratio and PLR. Therefore, a large-scale prospective study is needed to validate our results. Second, due to the low incidence of Xp11.2 tRCC, our sample size was relatively small, warranting a large-scale study. Third, several other factors that are influential to inflammation such as smoking habits and life styles were not included in the study.

Conclusions
In summary, we found that the NLR, CRP/Alb ratio and PLR were all potential markers for the survival of Xp11.2 tRCC; thus, they could be considered for clinical decision-making. Among them, the NLR is an independent predictor of both DFS and OS for patients with Xp11.2 tRCC and can be used to predict the surgical outcomes of Xp11.2 tRCC patients who underwent full resection.