FAM83A mRNA was upregulated in LUSC tissues. 555 samples (503 cancerous tissues and 52 normal tissues) from TCGA database were included. We found that FAM83A was significantly upregulated in LUSC tissues compared to normal tissues (median value: 13.464 transcript per million vs 0.411 transcript per million, P < 0.001, Fig. 1A). In subgroup analysis, FAM83A mRNA was upregulated in LUSC-not otherwise specified (NOS) type, but not in basaloid, papillary and small cell types based on histology subtype. Besides, FAM83A was upregulated in LUSC tissue of stage 1, 2 and 3 compared with normal tissues, as well as in LUSC tissues of N0, N1 and N2. Compared to normal controls, FAM83A mRNA was overexpressed in all patient subgroups based on age, race, gender and smoking habit (all P values < 0.001, Fig. 1B-H) except the subgroup of patients aged 21–40 years old group. By searching the Oncomine database, a total of 2 GEO-sourced datasets were found. The meta-analysis revealed that FAM83A mRNA levels were dramatically higher in LUSC than in normal lung tissues (P = 0.032, Fig. 2A). Moreover, as shown in Fig. 2B-C, results from the dataset was consistent with finding of the above meta-analysis. To verify the expression level of FAM83A protein in LUSC tissues. We performed IHC in 132 pairs of LUSC and paracancerous tissues (Fig. 3). No significant relationship was identified between FAM83A expression and clinicopathological features such as age, gender, smoking, drinking, T stage, N stage and differentiation (Table 1). FAM83A was overexpressed in 78 (59.1%) cancerous tissues and 19(14.4%) pancancerous tissues (P < 0.001).
Table 1
The correlation of clinicopathologic variables with FAM83A expression in LUSC samples
Clinicopathological features | FAM83A overexpression | Pa value |
No (n = 54) | Yes (n = 78) |
Age | | | 0.369 |
< 65 | 25 | 30 | |
≥ 65 | 29 | 48 | |
Gender | | | 0.279 |
Female | 23 | 26 | |
Male | 31 | 52 | |
Smoking | | | 0.734 |
Never or light | 38 | 57 | |
Heavy | 16 | 21 | |
Drinking | | | 0.135 |
Never or light | 46 | 58 | |
Heavy | 8 | 20 | |
Differentiation | | | 0.497 |
Well | 19 | 22 | |
Moderate | 15 | 29 | |
Poor | 20 | 27 | |
T stage | | | 0.404 |
T1 | 20 | 22 | |
T2 | 23 | 33 | |
T3 | 11 | 23 | |
N stage | | | 0.441 |
N0 | 18 | 19 | |
N1 | 13 | 23 | |
N2 | 18 | 23 | |
N3 | 5 | 13 | |
Pa: Chi-square test. |
The prognostic value of FAM83A in LUSC. Based on TCGA database, high level of FAM83A mRNA was significantly associated with poorer overall survival (OS) of LUSC patients (P = 0.00048, Fig. 4A). We further browsed Kaplan-Meier database, higher FAM83A mRNA expression level also predicted poorer 5- and 10- years’ OS (both P < 0.001) (Fig. 4B-C). Furtherly, we analyzed the prognosis value of FAM83A protein level using our own data. Of the 132 patients who provided formalin-fixed paraffin-embedded (FFPE) cancer tissues, 64 (48.5%) survived more than 5 years after pneumonectomy and 68 (51.5%) died during the follow-up period. The mean OS time for all patients was 50.5 ± 17.7 months (range 15–82 months) and mean progression-free survival (PFS) time was 45.5 ± 20.6 months (range 9–82 months). Kaplan-Meier analyses using the log-rank test were performed to calculate the effect of these clinicopathologic factors on OS and PFS rates. High FAM83A protein expression was significantly associated with decreased 5-years’ OS (P = 0.007) and PFS (P = 0.007) (Fig. 5, Table 2). Furthermore, via multivariate analysis, FAM83A expression level was an independent prognostic factor for OS (hazard ratio (HR) (95%CI): 2.160 (1.374–3.396), P = 0.006), as well as PFS (HR (95%CI): 2.266 (1.367–3.756), P = 0.002, Table 2). Besides, T and N stages were significant prognostic indicators for PFS (P = 0.008 and P = 0.033, respectively).
Table 2
Univariate and multivariate analyses of prognostic variables for LUSC patients
| OS Univariate analysis | OS Multivariate analysis | PFS Univariate analysis | PFS Multivariate analysis |
Variables | HR (95% CI) | P value | HR (95% CI) | P value | HR (95% CI) | P value | HR(95% CI) | P value |
Gender | | | | | | | | |
Female | Ref | - | | | Ref | - | | |
Male | 0.935(0.569–1.539) | 0.793 | | | 0.958(0.599–1.533) | 0.858 | | |
Age | | | | | | | | |
<65 years-old | Ref | - | | | Ref | - | | |
≥65 years-old | 1.024(0.632–1.660) | 0.923 | | | 1.027(0.650–1.624) | 0.908 | | |
Smoking | | | | | | | | |
Never or light | Ref | - | | | Ref | - | | |
Heavy | 1.589(0.961–2.627) | 0.071 | | | 0.648(0.401–1.047) | 0.076 | | |
Drinking | | | | | | 0.437 | | |
Never or light | Ref | - | | | Ref | - | | |
Heavy | 1.319(0.753–2.311) | 0.333 | | | 0.809(0.472–1.388) | 0.442 | | |
Differentiation | | 0.240 | | | | 0.490 | | |
Poor | Ref | - | | | Ref | - | | |
Median | 1.606(0.891–2.894) | 0.115 | | | 1.319(.766-2.274) | 0.318 | | |
Well | 1.143(0.609–2.146) | 0.677 | | | 0.993(0.557–1.772) | 0.982 | | |
T stage | | 0.049* | | 0.080 | | 0.011* | | 0.008* |
T1 | Ref | - | Ref | - | Ref | - | Ref | - |
T2 | 1.557(0.848–2.858) | 0.153 | 1.277 (0.688–2.373) | 0.438 | 1.522(0.853–2.713) | 0.155 | 1.243 (0.689–2.245) | 0.470 |
T3 | 2.202(1.154–4.204) | 0.017* | 2.057 (1.065–3.971) | 0.032* | 2.494(1.363–4.565) | 0.003* | 2.446 (1.323–4.523) | 0.004* |
N stage | | 0.024* | | 0.053 | | 0.024* | | 0.033* |
N0 | Ref | - | Ref | - | Ref | - | Ref | - |
N1 | 1.723(0.836–3.551) | 0.140 | 1.741 (0.832–3.644) | 0.141 | 1.553(0.800-3.015) | 0.193 | 1.605 (0.817–3.154) | 0.170 |
N2 | 1.981(0.985–3.986) | 0.055 | 1.903 (0.936–3.869) | 0.076 | 1.762(0.928–3.347) | 0.083 | 1.717 (0.895–3.294) | 0.104 |
N3 | 3.334(1.535–7.242) | 0.002* | 3.076 (1.380–6.856) | 0.006* | 3.058(1.487–6.287) | 0.002* | 3.079 (1.452–6.532) | 0.003* |
FAM83A | | | | | | | | |
Low | Ref | - | Ref | - | Ref | - | Ref | - |
High | 2.058(1.220–3.471) | 0.007* | 2.160 (1.374–3.396) | 0.006* | 1.940(1.194–3.151) | 0.007* | 2.266 (1.367–3.756) | 0.002* |