ONS/ONCC Exam Questions and Answers
(Verified Answers) Most Recent exam
COMPLETE (2026) UPDATE!!
DOMAIN 1: Cancer Pathophysiology, Genetics & Prevention (10 Questions)
Question 1 (Multiple-Choice)
A 58-year-old patient asks why smoking cessation after 30 years still reduces cancer risk. The
nurse explains that the multistep carcinogenesis model involves initiation, promotion, and
progression. Which statement best describes the promotion phase?
A. A single irreversible mutation in a stem cell DNA sequence caused by a carcinogen
B. The clonal expansion of initiated cells through repeated exposure to promoting agents
C. The acquisition of invasive and metastatic capabilities by a benign tumor
D. The repair of damaged DNA by tumor suppressor genes such as TP53
[CORRECT: B]
Rationale: The promotion phase is characterized by the clonal expansion of initiated cells
through repeated exposure to promoting agents (e.g., hormones, chronic irritation). This phase
is reversible if the promoting stimulus is removed, which explains why smoking cessation
reduces risk even after decades of exposure. Initiation (Option A) is the irreversible DNA
mutation; progression (Option C) involves invasion and metastasis; TP53-mediated DNA repair
(Option D) is a tumor suppressor function, not a phase of carcinogenesis.
Question 2 (SATA)
Which of the following are true regarding the TP53 tumor suppressor gene and its role in
carcinogenesis? (Select all that apply.)
A. TP53 is located on chromosome 17p13.1
B. TP53 encodes the p53 protein, which functions as a transcription factor
C. Mutant TP53 allows cells with DNA damage to proceed through the G1/S checkpoint
D. TP53 mutations are found in more than 50% of human cancers
E. TP53 is an oncogene that promotes uncontrolled cellular proliferation
,[CORRECT: A, B, C, D]
Rationale: TP53 is located on chromosome 17p13.1 and encodes the p53 protein, a critical
transcription factor that regulates the cell cycle, apoptosis, and DNA repair. When TP53 is
mutated, the G1/S checkpoint is compromised, allowing damaged DNA to replicate. TP53
mutations are the most common genetic alterations in human malignancies, present in over
50% of cancers. TP53 is a tumor suppressor gene, not an oncogene (Option E is incorrect).
Question 3 (Multiple-Choice)
A patient with a TP53 germline mutation (Li-Fraumeni syndrome) develops a second primary
malignancy. The nurse recognizes that mutant p53 protein loses which critical function?
A. Activation of telomerase to maintain chromosomal integrity
B. Induction of cell cycle arrest and apoptosis in response to DNA damage
C. Promotion of angiogenesis via VEGF upregulation
D. Enhancement of glycolysis for rapid energy production in tumor cells
[CORRECT: B]
Rationale: Wild-type p53 functions as the "guardian of the genome" by inducing cell cycle arrest
(via p21) and apoptosis (via Bax and PUMA) in response to DNA damage. Mutant p53 loses this
function, allowing genomic instability and malignant transformation. Telomerase activation
(Option A), angiogenesis (Option C), and the Warburg effect/glycolysis (Option D) are not
primary functions of p53.
Question 4 (Calculation)
A 67-year-old patient undergoes right hemicolectomy for colon adenocarcinoma. Pathology
reveals a tumor measuring 4.2 cm invading through the muscularis propria into pericolorectal
tissues. Two of 18 regional lymph nodes are positive. No distant metastasis is identified. What is
the correct TNM stage group for this resection?
A. Stage I
B. Stage II
C. Stage III
D. Stage IV
[CORRECT: C]
Rationale: According to the AJCC 8th edition TNM staging for colon cancer: T3 = tumor invades
through the muscularis propria into pericolorectal tissues; N1 = 1–3 regional lymph nodes
, positive; M0 = no distant metastasis. T3N1M0 corresponds to Stage III colon adenocarcinoma.
Stage I is T1-2N0M0; Stage II is T3-4N0M0; Stage IV requires distant metastasis (M1).
Question 5 (Multiple-Choice)
The oncologist explains to the patient in Question 4 that the T3N1M0 staging has prognostic
implications. Which factor most significantly worsens the prognosis in Stage III colon cancer?
A. Tumor location in the ascending colon versus descending colon
B. Presence of lymphovascular invasion and high-grade histology
C. Patient age greater than 65 years at diagnosis
D. Microsatellite instability-high (MSI-H) status
[CORRECT: B]
Rationale: In Stage III colon cancer, poor prognostic factors include lymphovascular invasion,
high-grade/poorly differentiated histology, bowel perforation, and clinical obstruction. These
features increase the risk of recurrence and guide adjuvant chemotherapy decisions. MSI-H
status (Option D) is actually associated with a better prognosis in Stage II disease and predicts
response to immunotherapy. Age and tumor location are less significant independent
prognostic factors.
Question 6 (Calculation)
A patient is diagnosed with T2N1M0 colon adenocarcinoma. The tumor measures 3.5 cm and
invades the muscularis propria without penetrating through it. One regional lymph node is
positive. What is the 5-year relative survival rate approximately associated with this stage?
A. >90%
B. 70–85%
C. 40–60%
D. <20%
[CORRECT: B]
Rationale: T2N1M0 colon cancer is classified as Stage IIIA (T1-2N1M0). The 5-year relative
survival for Stage IIIA colon cancer is approximately 83% per SEER data. Stage I is >90%; Stage II
is 75–85%; Stage IIIC drops to 40–53%; and Stage IV is <20%. The presence of nodal involvement
(N1) upstages the patient from Stage I to Stage III, significantly impacting survival statistics.
(Verified Answers) Most Recent exam
COMPLETE (2026) UPDATE!!
DOMAIN 1: Cancer Pathophysiology, Genetics & Prevention (10 Questions)
Question 1 (Multiple-Choice)
A 58-year-old patient asks why smoking cessation after 30 years still reduces cancer risk. The
nurse explains that the multistep carcinogenesis model involves initiation, promotion, and
progression. Which statement best describes the promotion phase?
A. A single irreversible mutation in a stem cell DNA sequence caused by a carcinogen
B. The clonal expansion of initiated cells through repeated exposure to promoting agents
C. The acquisition of invasive and metastatic capabilities by a benign tumor
D. The repair of damaged DNA by tumor suppressor genes such as TP53
[CORRECT: B]
Rationale: The promotion phase is characterized by the clonal expansion of initiated cells
through repeated exposure to promoting agents (e.g., hormones, chronic irritation). This phase
is reversible if the promoting stimulus is removed, which explains why smoking cessation
reduces risk even after decades of exposure. Initiation (Option A) is the irreversible DNA
mutation; progression (Option C) involves invasion and metastasis; TP53-mediated DNA repair
(Option D) is a tumor suppressor function, not a phase of carcinogenesis.
Question 2 (SATA)
Which of the following are true regarding the TP53 tumor suppressor gene and its role in
carcinogenesis? (Select all that apply.)
A. TP53 is located on chromosome 17p13.1
B. TP53 encodes the p53 protein, which functions as a transcription factor
C. Mutant TP53 allows cells with DNA damage to proceed through the G1/S checkpoint
D. TP53 mutations are found in more than 50% of human cancers
E. TP53 is an oncogene that promotes uncontrolled cellular proliferation
,[CORRECT: A, B, C, D]
Rationale: TP53 is located on chromosome 17p13.1 and encodes the p53 protein, a critical
transcription factor that regulates the cell cycle, apoptosis, and DNA repair. When TP53 is
mutated, the G1/S checkpoint is compromised, allowing damaged DNA to replicate. TP53
mutations are the most common genetic alterations in human malignancies, present in over
50% of cancers. TP53 is a tumor suppressor gene, not an oncogene (Option E is incorrect).
Question 3 (Multiple-Choice)
A patient with a TP53 germline mutation (Li-Fraumeni syndrome) develops a second primary
malignancy. The nurse recognizes that mutant p53 protein loses which critical function?
A. Activation of telomerase to maintain chromosomal integrity
B. Induction of cell cycle arrest and apoptosis in response to DNA damage
C. Promotion of angiogenesis via VEGF upregulation
D. Enhancement of glycolysis for rapid energy production in tumor cells
[CORRECT: B]
Rationale: Wild-type p53 functions as the "guardian of the genome" by inducing cell cycle arrest
(via p21) and apoptosis (via Bax and PUMA) in response to DNA damage. Mutant p53 loses this
function, allowing genomic instability and malignant transformation. Telomerase activation
(Option A), angiogenesis (Option C), and the Warburg effect/glycolysis (Option D) are not
primary functions of p53.
Question 4 (Calculation)
A 67-year-old patient undergoes right hemicolectomy for colon adenocarcinoma. Pathology
reveals a tumor measuring 4.2 cm invading through the muscularis propria into pericolorectal
tissues. Two of 18 regional lymph nodes are positive. No distant metastasis is identified. What is
the correct TNM stage group for this resection?
A. Stage I
B. Stage II
C. Stage III
D. Stage IV
[CORRECT: C]
Rationale: According to the AJCC 8th edition TNM staging for colon cancer: T3 = tumor invades
through the muscularis propria into pericolorectal tissues; N1 = 1–3 regional lymph nodes
, positive; M0 = no distant metastasis. T3N1M0 corresponds to Stage III colon adenocarcinoma.
Stage I is T1-2N0M0; Stage II is T3-4N0M0; Stage IV requires distant metastasis (M1).
Question 5 (Multiple-Choice)
The oncologist explains to the patient in Question 4 that the T3N1M0 staging has prognostic
implications. Which factor most significantly worsens the prognosis in Stage III colon cancer?
A. Tumor location in the ascending colon versus descending colon
B. Presence of lymphovascular invasion and high-grade histology
C. Patient age greater than 65 years at diagnosis
D. Microsatellite instability-high (MSI-H) status
[CORRECT: B]
Rationale: In Stage III colon cancer, poor prognostic factors include lymphovascular invasion,
high-grade/poorly differentiated histology, bowel perforation, and clinical obstruction. These
features increase the risk of recurrence and guide adjuvant chemotherapy decisions. MSI-H
status (Option D) is actually associated with a better prognosis in Stage II disease and predicts
response to immunotherapy. Age and tumor location are less significant independent
prognostic factors.
Question 6 (Calculation)
A patient is diagnosed with T2N1M0 colon adenocarcinoma. The tumor measures 3.5 cm and
invades the muscularis propria without penetrating through it. One regional lymph node is
positive. What is the 5-year relative survival rate approximately associated with this stage?
A. >90%
B. 70–85%
C. 40–60%
D. <20%
[CORRECT: B]
Rationale: T2N1M0 colon cancer is classified as Stage IIIA (T1-2N1M0). The 5-year relative
survival for Stage IIIA colon cancer is approximately 83% per SEER data. Stage I is >90%; Stage II
is 75–85%; Stage IIIC drops to 40–53%; and Stage IV is <20%. The presence of nodal involvement
(N1) upstages the patient from Stage I to Stage III, significantly impacting survival statistics.
