Spectra of antinuclear antibodies in patients with squamous cell carcinoma of the lung and of the head and neck

Abstract

Squamous cell carcinoma of the head and neck (HNSCC) and of the lung (LSCC) share some important risk factors, but differ substantially in terms of prognosis and treatment. A pulmonary nodule developing in patients with surgically cured HNSCC may pose a diagnostic dilemma. Markers able to distinguish these two common malignancies would be of major clinical importance. In this work we compared the spectrum of antinuclear antibodies (ANA) from 22 patients with SCCL to that of 40 patients with HNSCC. Patient sera were used to probe immunoblots of nuclear extracts from all four major lung cancer cell types, normal lung fibroblasts, cells cultured from a HNSCC, and keratinocytes cultured from the field cancerization. The ability to classify retrospectively LSCC from HNSCC based on serum ANA reactivities was determined by recursive partitioning analyses. We found that while both malignancies share reactivities to a small group of nuclear antigens, other reactivities are directed against proteins uniquely or preferentially expressed in either SCCL or in SCCHN cells. Our work shows that autoimmunity is a prominent feature of squamous cell carcinoma and suggests that molecular characterization of nuclear antigens recognized by ANAs may lead to the discovery of markers valuable to distinguish LSCC from HNSCC.

Fig. 1

(A) Immunoblots of nuclear extracts from LSCC cells (HTB-182 human lung squamous cell carcinoma from the ATCC) probed with sera from LSCC patients and (B) with sera from subjects without cancer. Patient and control sera were diluted 1:500. Secondary antibody, sheep anti-human IgG, diluted 1:2500.

Fig. 2

(A) Immunoblots of nuclear extracts from HNSCC cells probed with sera from patients with HNSCC and (B) with non-cancer control sera. Conditions related to primary and secondary antibodies were as in Fig. 1.

Fig. 3

Tree to distinguish sera from LSCC patients (n = 22) from non-cancer control sera (n = 40) using all eight antigen sets (h, s, q, a, l, n, x, m). Antigen variables selected by CART analyses are presented and labeled with the first letter designating the reactive antigen set, the second letter (g or m) designating the reactive isotype IgG or IgM, and the following number designating the antigen molecular mass in kDa. The fraction of cases correctly identified over the total number of cases is included for each terminal node.

Fig. 4

Tree to distinguish sera from patients with HNSCC (n = 40) from non-cancer control sera (n = 40) using all eight antigen sets (h, s, q, a, l, n, x, m). Antigen variables selected by CART analyses are presented and labeled as in Fig. 3.

Fig. 5

Tree to distinguish sera from patients with HNSCC (n = 40) from sera from LSCC patients (n = 22). Antigen variables selected by CART are presented and labeled as in Fig. 3.

Fig. 6

Diagrammatic summary of the results of two independent CART analyses identifying variables (nuclear antigens) listed in order of predicting ability for the diagnoses of HNSCC and LSCC from subjects without cancer, respectively. Antigen designation follows the nomenclature described in Fig. 3.