The primary Study hypothesis is that the ProLung Test will demonstrate safety and efficacy in the risk stratification of patients with pulmonary lesions identified by CT that are suspicious for lung cancer. A statistically significant result will indicate that patients with a high ProLung Test result have a greater risk of developing lung cancer than patients with a low test result.

There are three Specific Aims of this study:

1. Optimize and confirm the stability of the ProLung Test risk-stratification algorithm in patients with a diagnosis.
2. Externally validate the efficacy of the ProLung Test risk-stratification algorithm by comparing the test result to the conclusive patient diagnosis.
3. Assess the safety and tolerability of the ProLung Test procedures.

Study Design This Study consists of two distinct phases, Stabilization and Validation. The Study will collect data from multiple sites (3 to 12), and each site may enroll patients and collect data for the Stabilization and Validation Phases with a minimum of three sites for the Validation Phase.

Inclusion Criteria:

Subjects who meet all of the following criteria may be enrolled in this Study:

1. Subject is male or female, age 18 or older.

2. Subject has undergone CT scan of the lung(s) that indicates one or more nodules or lesions suspicious for lung cancer.

3. Subject's pulmonary nodule or lesion is greater than 4mm. Size is determined by the largest nodule or lesion dimension identified from CT imaging.

4. Subject meets one or more of the following conditions:

   • indicated for a tissue biopsy
   • indicated for surgical resection of the lung

5. Subject must be able to receive a ProLung Test

   • within 60 days of abnormal CT (Inclusion Criterion 2 & 3)
   • within 60 days prior to the tissue biopsy or surgical resection (Inclusion Criterion 4).

6. Subject is capable of understanding and agreeing to fulfill the requirements of this Protocol.

7. Subject has signed the IRB/IEC approved Informed Consent Form ("ICF").

Exclusion Criteria

The following criteria will disqualify a subject from enrollment into this Study:

1. Subject has an implanted electronic device in the chest.
2. Subject receiving therapy for suspected chest infection such as fungal infection or tuberculosis.
3. Subject with diagnosed malignancy other than lung cancer, non-melanoma skin cancer or any cancer in which the Principal Investigator does not suspect metastatic disease to the lung, who has 2 or more suspicious pulmonary nodules.
4. Subject has received an invasive medical or surgical procedure within the thoracic cavity within 30 days prior to the ProLung Test or within the previous 14 days for a bronchoscopic procedure.
5. Subject presents with an anomalous physical or anatomical condition that precludes ProLung Test measurement.
6. Subject will have undergone unusually strenuous exercise within 24 hours.
7. Subject who has significant systemic diseases such as uncontrolled diabetes, advanced heart failure, or a recent myocardial infarction, or other medical condition such as severe morbid obesity that in the judgment of the Principal Investigator would make him/her unsuitable for the Study.

Subjects with pulmonary lesions suspicious for lung cancer