Indian Journal of Pathology and Microbiology

: 2022  |  Volume : 65  |  Issue : 4  |  Page : 750--754

Prognostic significance of p16, VEGF, and p53 expression patterns, Krouse stage, and smoking status in sinonasal inverted papillomas

Betul Peker Cengiz 
 Department of Pathology, Yunus Emre State Hospital, Eskisehir, Turkey

Correspondence Address:
Betul Peker Cengiz
Department of Pathology, Yunus Emre State Hospital, Eskişehir - 26020


Aim: The aim of our study is to analyze the staining models for VEGF, p16, and p53, as well as to understand the biology of inverted papilloma caused by smoking. Materials and Methods: Thirty-one cases, diagnosed with sinonasal inverted papilloma between 2015 and 2019, were included. Demographic data such as age and gender, admission symptoms of the patients, and anatomical location, stage, surgical technique, and recurrence information were obtained from clinical follow-up files. Immunohistochemical staining for p16, VEGF, and p53 were performed on patient materials. Results: In our study, the female to male ratio was 9.33 with an average age of 53.137 ± 13.96 years. Of the patients, 17 were nonsmokers and 14 were smokers. No significant relationship was found between smoking status and relapse and dysplasia. In contrast, a significant relationship between the Krouse stage and dysplasia (P = 0.005) was observed. A similar significant relationship was observed between p16 immunohistochemical expression and dysplasia (P = 0.030). On the other hand, VEGF and p53 immunohistochemical expressions were not significantly related with dysplasia and recurrence. Conclusions: Inverted papillomas are benign tumors that clinically give symptoms similar to nasal polyps. However, recurrence and malignant transformation potential exist and the factors causing this risk are not clearly identified. In our study, no malignant transformation was observed in patients who were admitted to our hospital.

How to cite this article:
Cengiz BP. Prognostic significance of p16, VEGF, and p53 expression patterns, Krouse stage, and smoking status in sinonasal inverted papillomas.Indian J Pathol Microbiol 2022;65:750-754

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Cengiz BP. Prognostic significance of p16, VEGF, and p53 expression patterns, Krouse stage, and smoking status in sinonasal inverted papillomas. Indian J Pathol Microbiol [serial online] 2022 [cited 2022 Dec 7 ];65:750-754
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The World Health Organization (WHO) classifies the sinonasal papillomas histologically into three subgroups as inverted, fungiform, and oncocytic papillomas.[1],[2],[3] Sinonasal inverted papilloma (SNIP) is a rare benign tumor of the nose and paranasal sinuses. Sinonasal inverted papilloma usually originates from the ectodermal Schneiderian mucosa of the lateral nasal wall.[4] Schneiderian epithelium consists of cylindrical ciliated epithelium and contains a small amount of goblet cells.[5] Sinonasal inverted papillomas are formed by invagination and proliferation of the Schneiderian epithelium into the stromal area. It was first described in 1854 by Wang et al.[1] Its annual incidence has been reported as 0.2–1.5/100000 and constitutes 0.5%–4% of primary nasal tumors.[1],[6] In Caucasians, it is observed more commonly in men with a male/female ratio of 3.4: 1.[7] Although SNIP usually appears between 5th and 7th decades, the average age of occurrence is 53 years. On the other hand, in the literature, sporadic cases have been reported in children, adolescents, and young individuals.[7]

Even though nasal septum, frontal sinus, and sphenoid sinus are the regions of involvement, SNIP most often originates from lateral nasal wall (89%).[8] The most common clinical symptom is unilateral nasal obstruction and is seen in 80%–98% of the cases.[7] Other symptoms are runny nose, tearing, anosmia, proptosis, and diplopia. On the other hand, the most common symptom in malignant SNIP is nasal bleeding.[7] Although etiology of the disease is still unknown, allergy, chronic rhinosinusitis, environmental pollution, and smoking are among the most studied etiologic factors.[9] Today, the most important factor accused in etiology is Human papilloma virus (HPV) infections.[9],[10]

Even though having completely benign histopathological features, SNIPs have high growth potential and high rates of recurrence have been reported.

In this article, our aim is to analyze the staining models for VEGF, p16, and p53, as well as to understand the inverted papilloma biology by evaluating the smoking status of the patients.

 Materials and Methods

Thirty-one cases diagnosed with sinonasal inverted papilloma in the pathology clinic of our hospital between the years 2015 and 2019 were included. Demographic data such as age and gender, admission symptoms of the patients, and anatomical location, stage, surgical technique, and recurrence information were obtained from clinical follow-up files.

Sinonasal computed tomography was performed before the surgery and all patients were staged according to the Krouse classification system [Table 1]. Thereafter, all patients underwent endoscopic and Caldwell-Luc surgery.{Table 1}

All the materials were sampled after the surgical samples were fixed in 10% neutral buffered formalin. All samples were processed in an automatic tissue tracking device, fixed in paraffin blocks, followed by staining with H and E dye. H and E-stained sections were reevaluated for dysplasia and samples were divided into 4 groups as no dysplasia, Grade 1 (low grade), Grade 2 (moderate), and Grade 3 (high grade) dysplasia. Sections were taken on positive charged slides for immunohistochemical staining. In these sections, p53 (Dako Omnis, Clone DO-7), VEGF (Dako Omnis, Clone VG1), and p16 (Dako Omnis, Clone CD2A1_Human) immunohistochemical dyes were applied in an automatic Dako Omnis device. Positive and negative controls were used for VEGF, p53, and p16 immunohistochemical staining. VEGF and p53 immunohistochemical stains were evaluated by a semi-quantitative method rated from 1 to 4. Less than 10% staining, 20%–24% staining, 25%–50% staining, and more than 51% staining were accepted as score 1, score 2, score 3, and score 4, respectively. To evaluate p16 immunohistochemical staining, a 2-degree system was used as positive or negative, in which nuclear and cytoplasmic staining of more than or equal to 70% was considered positive and single-cell staining and no staining were accepted as negative for p16.

Ethics committee approval for our study was obtained from Faculty of Medicine (Issue: 25403353-050.99-E.27535).

Continuous data are given as Mean ± Standard Deviation. Categorical data are given as percentage (%). Shapiro–Wilk test was used to evaluate the normal distribution of data. For the comparison of groups showing normal distribution, independent sample t-test analysis was used for cases with two groups, and one-way analysis of variance (One-Way ANOVA) for cases with three or more groups. Pearson Chi-Square and Pearson's Exact Chi-Square analyzes were used in the analysis of the cross tables. IBM SPSS Statistics 21.0 program was used for analyzes. The statistical significance level was accepted as P < 0.05.


Of 31 patients who underwent surgery for inverted papilloma [Figure 1]a, 28 were male and 3 were female with a male/female ratio of 9.33. The age range of the patients was 20–86 years, with an average age of 53.137 ± 13.96 years. All patients were admitted to the hospital with complaints of nasal congestion, breathing, and anosmia. In addition, 2 patients had complaint of nasal mass protruding from nostrils. The follow-up period of patients after pathologic diagnosis was minimum 4 months and maximum 60 months. The clinical follow-up files revealed that 3 patients (9.7%) had undergone a previous inverted papilloma surgery, and only 1 of them had two previous surgeries. These smoking patients continued to smoke after their first surgery and recurrence was observed in the cases after 120 months, 4 months, and 36 months. While 17 of the patients did not smoke, 14 of them were smokers. No significant relationship was found between smoking and recurrence (P = 0.081) and dysplasia (P = 0.646). According to the Krouse classification system, 10 patients were evaluated as Stage 1, 7 patients as Stage 2, 13 patients as Stage 3, and 1 patient as Stage 4 [Figure 1]b. Although no significant relationship was observed between stage and recurrence (P = 0.128), there was a significant relationship between stage and dysplasia (P = 0.005) [Table 2]. In p53 immunohistochemical staining, 21 patients had score 1, 8 patients had score 2, and 3 patients had score 3. There was no significant relationship between p53 staining pattern and recurrence (P = 0.397) or dysplasia (P = 0.052) [Figure 1]c. In p16 immunohistochemical staining, 17 patients had no immunoreactivity (negative), and 14 patients had immunoreactivity (positive) [Figure 1]d. Although there was no significant relationship between p16 staining pattern and recurrence (P = 0.576), a significant relationship was found with dysplasia (P = 0.030). In VEGF immunohistochemical staining, 25 patients had score 1, 4 patients had score 2, and 2 patients had score 3 staining. There was no significant relationship between VEGF staining pattern and recurrence (P = 0.797) or dysplasia (P = 0.310) [Table 3].{Figure 1}{Table 2}{Table 3}


Sinonasal inverted papilloma is a benign sinonasal epithelial tumor, but unlike other benign tumors, it exhibits remarkable aggressive behavior such as invasiveness, recurrence, and malignant transformation.[11] Therefore, determining and understanding clinical and histopathological risk factors is important for clinical follow-up of patients.[11]

The etiology of SNIP is not clearly established today. There are many studies on this subject in the literature. The most frequently studied factors are Human papilloma virus (HPV), Epstein Barr Virus (EBV), inflammatory infiltrate, smoking, occupational and environmental dust exposure, cell cycle regulatory proteins, angiogenic factors, and chronic inflammation.[1],[5]

Some of the factors associated with angiogenesis are very important in the growth of SNIP. Vascular endothelial growth factor (VEGF) plays an important role in mediating neoangiogenesis during tumor progression by promoting endothelial cell mitosis and migration, increasing vascular permeability, and forming new blood vessels.[1] Liu et al.[12] found that compared to the control tissues, the immunohistochemical staining, mRNA expression, and protein levels for VEGF were higher in SNIP tissues, and there was a significant correlation between VEGF expression and disease severity. Similar findings were reported by Bilic et al.[13] In another study, Kong et al.[14] have found that the expression of VEGF in the epithelium is significantly higher in severe dysplasia than in mild dysplasia and significantly higher in mild dysplasia than inverted papilloma without dysplasia. In our study, no similar relationship was observed, which can be attributed to the fact that there was only 1 patient with severe dysplasia.

Smoking is the most important risk factor in the formation and recurrence of neoplasms in the head and neck region. Although, according to the literature, smoking does not induce the development of SNIP, it has been reported to contribute to the recurrence and malign transformation of SNIP.[1],[11] Occupational and industrial exposures have been also reported as other contributing factors in SNIP etiology.[1],[11] Nevertheless, we found no significant relationship between smoking status and relapse and dysplasia in our study.

High-risk Human papilloma virus (HPV) is a double-chain DNA virus, and after infecting the host cell, it causes two viral oncogene expressions known as E6 and E7. E6 oncoprotein initiates carcinogenesis by targeting the p53.[5] The activated E2F promotes the progression of the cell cycle. Functional inactivation of the pRb by E7 oncoprotein results in over-expression of p16. Therefore, it makes p16 a reasonable marker for the presence of high-risk human papillomavirus.[15] Especially in head and neck cancers, p16 positivity is considered as an important marker for the presence of high-risk HPV, but this has not been demonstrated in SNIP yet.[7],[15] In our study, although a significant relationship was found between p16 and dysplasia observed in the epithelium, we cannot make a definitive comment because there was no carcinoma in our patient series.

P53 is an important tumor suppressor gene in a key position involved in cell proliferation. It controls the cell cycle and directs the cell to apoptosis in cells with irreparable DNA damage. Kandoth et al.[16] stated that the most frequently mutated gene in cancer cells is p53. Many studies in the literature have shown that cancer cells with mutant p53 protein divide faster than cancer cells without, as well as show invasion and metastasis.[17] Synthesis of mutant p53 is higher in tumor cells. Although the most common genetic change in head and neck cancers is the p53 mutation in many studies, we did not find a significant relationship between p53 and the degree of dysplasia and recurrence in our study, which can be resulted from the lack of patients with carcinoma in the present study. In the study of Lin et al.,[18] p53 mutation has been shown to be important in the transition from SNIP to carcinoma. On the other hand, literature shows that the relationship between cell cycle regulatory factors and the progression of carcinogenesis and dysplasia are not clearly understood.

Relapse occurs after the first treatment, mostly at the same site, with an average time of 31 months.[19] The type of surgery and the recurrence rates are closely related. The highest recurrence rate was observed in the nonendoscopic nasal approach (50%), while the lowest recurrence rate (10%) was reported in cases where endoscopic and open surgery were combined.[20] There was a recurrence in 3 of our cases (9.7%). The surgery of these patients was performed by endoscopic sinus surgery and the tumor recurred in the same location in all patients. Although the frequency of recurrence depends on the type of surgery, relapses have been reported in those who continue to smoke after the first surgical procedure.[21] In our cases, recurrence was observed at the earliest 4 months and after 120 months at the latest in these 3 cases continued smoking after the surgery. However, we found no statistically significant relationship between relapse and smoking in our study. Among the factors determining the prognosis of SNIP, the malignant transformation stands out. On the other hand, the malign transformation has been reported to be about 11% for SNIP; the most troublesome problem in these patients is the recurrence.[22] There is no consensus in the literature on the Krouse staging system to predict the recurrence rate of SNIP. Lisan et al.[23] stated that there is a 51% increase in the risk of recurrence in SNIP cases classified as Krouse stage T3 when compared Krouse stage T2, but no differences in recurrence rate were found between stage T1 and T2 disease or between stage T3 and T4 disease. In our study, no correlation was found between the Krouse stage and recurrence risk.

As a result, SNIPs are benign tumors that clinically present with symptoms similar to nasal polyps. However, because of its significant risk of malignant transformation and high recurrence rate, it is important to determine the diagnostic and therapeutic strategies for this disease. Although the rate of recurrence and malignancy in the literature is about 11%, we did not observe malignant transformation among our cases. We observed recurrence in only 3 of our cases, which might be resulted from the insufficient number of patients included in our study. Therefore, it is mandatory to conduct larger statistical studies to determine the relationship of SNIP with malignancy and recurrence rates.

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Conflicts of interest

There are no conflicts of interest.


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